diff --git a/.evergreen/config.yml b/.evergreen/config.yml
index 196fc0332..c0577ea6f 100644
--- a/.evergreen/config.yml
+++ b/.evergreen/config.yml
@@ -336,15 +336,9 @@ functions:
         script: |
           set -o xtrace
           set -o errexit
-
-          if [ "${SWIFT_MINOR_VERSION}" = "main-snapshot" ]; then
-              export SWIFT_VERSION="${SWIFT_MINOR_VERSION}"
-          else
-              # otherwise, find the latest patch release for the specified version
-              ${PYTHON} -m virtualenv ./requests-env
-              ./requests-env/${VENV_BIN_DIR}/python3 -m pip install requests
-              export SWIFT_VERSION="$(./requests-env/${VENV_BIN_DIR}/python3 .evergreen/get_latest_swift_patch.py ${SWIFT_MINOR_VERSION})"
-          fi
+          ${PYTHON} -m virtualenv ./requests-env
+          ./requests-env/${VENV_BIN_DIR}/python3 -m pip install requests
+          export SWIFT_VERSION="$(./requests-env/${VENV_BIN_DIR}/python3 .evergreen/get_latest_swift_patch.py ${SWIFT_MINOR_VERSION})"
           echo "SWIFT_VERSION: $SWIFT_VERSION" > swift-version.yml
           cat swift-version.yml
     - command: expansions.update
@@ -620,6 +614,72 @@ tasks:
             MONGODB_VERSION: "5.0"
             TOPOLOGY: "sharded_cluster"
         - func: "run tests"
+  
+    - name: "test-5.0-load_balancer"
+      tags: ["5.0", "load-balancer"]
+      commands:
+        - func: "prepare resources"
+        - func: "fix absolute paths"
+        - func: "bootstrap mongo-orchestration"
+          vars:
+            MONGODB_VERSION: "5.0"
+            TOPOLOGY: "sharded_cluster"
+            LOAD_BALANCER: "true"
+        - func: start-load-balancer
+        - func: "run-lb-tests"
+          vars:
+            TOPOLOGY: "load_balanced"
+        - func: stop-load-balancer
+
+    - name: "test-6.0-standalone"
+      tags: ["6.0", "standalone"]
+      commands:
+        - func: "prepare resources"
+        - func: "fix absolute paths"
+        - func: "bootstrap mongo-orchestration"
+          vars:
+            MONGODB_VERSION: "6.0"
+            TOPOLOGY: "server"
+        - func: "run tests"
+
+    - name: "test-6.0-replica_set"
+      tags: ["6.0", "replica_set"]
+      commands:
+        - func: "prepare resources"
+        - func: "fix absolute paths"
+        - func: "bootstrap mongo-orchestration"
+          vars:
+            MONGODB_VERSION: "6.0"
+            TOPOLOGY: "replica_set"
+        - func: "run tests"
+
+    - name: "test-6.0-sharded_cluster"
+      tags: ["6.0", "sharded_cluster"]
+      exec_timeout_secs: 3600 # TODO SWIFT-1410: remove
+      commands:
+        - func: "prepare resources"
+        - func: "fix absolute paths"
+        - func: "bootstrap mongo-orchestration"
+          vars:
+            MONGODB_VERSION: "6.0"
+            TOPOLOGY: "sharded_cluster"
+        - func: "run tests"
+
+    - name: "test-6.0-load_balancer"
+      tags: ["6.0", "load-balancer"]
+      commands:
+        - func: "prepare resources"
+        - func: "fix absolute paths"
+        - func: "bootstrap mongo-orchestration"
+          vars:
+            MONGODB_VERSION: "6.0"
+            TOPOLOGY: "sharded_cluster"
+            LOAD_BALANCER: "true"
+        - func: start-load-balancer
+        - func: "run-lb-tests"
+          vars:
+            TOPOLOGY: "load_balanced"
+        - func: stop-load-balancer
 
     - name: "test-latest-standalone"
       tags: ["latest", "standalone"]
@@ -671,6 +731,56 @@ tasks:
             TOPOLOGY: "load_balanced"
         - func: stop-load-balancer
 
+    - name: "test-rapid-standalone"
+      tags: ["rapid", "standalone"]
+      commands:
+        - func: "prepare resources"
+        - func: "fix absolute paths"
+        - func: "bootstrap mongo-orchestration"
+          vars:
+            MONGODB_VERSION: "rapid"
+            TOPOLOGY: "server"
+        - func: "run tests"
+
+    - name: "test-rapid-replica_set"
+      tags: ["rapid", "replica_set"]
+      commands:
+        - func: "prepare resources"
+        - func: "fix absolute paths"
+        - func: "bootstrap mongo-orchestration"
+          vars:
+            MONGODB_VERSION: "rapid"
+            TOPOLOGY: "replica_set"
+        - func: "run tests"
+
+    - name: "test-rapid-sharded_cluster"
+      tags: ["rapid", "sharded_cluster"]
+      exec_timeout_secs: 3600 # TODO SWIFT-1410: remove
+      commands:
+        - func: "prepare resources"
+        - func: "fix absolute paths"
+        - func: "bootstrap mongo-orchestration"
+          vars:
+            MONGODB_VERSION: "rapid"
+            TOPOLOGY: "sharded_cluster"
+        - func: "run tests"
+  
+    - name: "test-rapid-load_balancer"
+      tags: ["rapid", "load-balancer"]
+      commands:
+        - func: "prepare resources"
+        - func: "fix absolute paths"
+        - func: "bootstrap mongo-orchestration"
+          vars:
+            MONGODB_VERSION: "rapid"
+            TOPOLOGY: "sharded_cluster"
+            LOAD_BALANCER: "true"
+        - func: start-load-balancer
+        - func: "run-lb-tests"
+          vars:
+            TOPOLOGY: "load_balanced"
+        - func: stop-load-balancer
+
     - name: "test-atlas-connectivity"
       tags: ["atlas-connect"]
       commands:
@@ -1049,6 +1159,14 @@ axes:
         display_name: "latest"
         variables:
            MONGODB_VERSION: "latest"
+      - id: "rapid"
+        display_name: "rapid"
+        variables:
+           MONGODB_VERSION: "rapid"
+      - id: "6.0"
+        display_name: "6.0"
+        variables:
+          MONGODB_VERSION: "6.0"
       - id: "5.0"
         display_name: "5.0"
         variables:
@@ -1087,6 +1205,13 @@ axes:
           PYTHON: "/opt/mongodbtoolchain/v3/bin/python3"
           VENV_BIN_DIR: "bin"
 
+      - id: macos-10.14
+        display_name: "macOS 10.14"
+        run_on: macos-1014
+        variables:
+          PYTHON: "/opt/mongodbtoolchain/v3/bin/python3"
+          VENV_BIN_DIR: "bin"
+
       - id: macos-11
         display_name: "macOS 11"
         run_on: macos-1100
@@ -1112,10 +1237,6 @@ axes:
   - id: swift-version
     display_name: "Swift"
     values:
-      - id: "5.1"
-        display_name: "Swift 5.1"
-        variables:
-           SWIFT_MINOR_VERSION: "5.1"
       - id: "5.2"
         display_name: "Swift 5.2"
         variables:
@@ -1250,18 +1371,21 @@ buildvariants:
 
 - matrix_name: "min-version-compile"
   matrix_spec:
-  # Ubuntu 20.04 does not have Swift 5.1 toolchains.
     os-fully-featured:
-      - "macos-11"
-      - "ubuntu-18.04"
-    swift-version: "5.1"
+      - macos-10.14
+      - ubuntu-18.04
+      - ubuntu-20.04
+    swift-version: "5.2"
   display_name: "Compile ${swift-version} ${os-fully-featured}"
   tasks:
     - "compile"
 
 - matrix_name: "tests-all"
   matrix_spec:
-    os-fully-featured: "*"
+    os-fully-featured:
+      - macos-11
+      - ubuntu-18.04
+      - ubuntu-20.04
     swift-version:
       - "5.5"
       - "5.6"
@@ -1269,8 +1393,10 @@ buildvariants:
     ssl-auth: "*"
   display_name: "${swift-version} ${os-fully-featured} ${ssl-auth}"
   tasks:
+     - ".rapid !.load-balancer"
      - ".latest !.load-balancer"
-     - ".5.0"
+     - ".6.0 !.load-balancer"
+     - ".5.0 !.load-balancer"
      - ".4.4"
      - ".4.2"
      - ".4.0"
@@ -1302,7 +1428,10 @@ buildvariants:
 
 - matrix_name: "atlas-connect"
   matrix_spec:
-    os-fully-featured: "*"
+    os-fully-featured:
+      - macos-11
+      - ubuntu-18.04
+      - ubuntu-20.04
     swift-version:
       - "5.5"
       - "5.6"
@@ -1340,6 +1469,8 @@ buildvariants:
       - "ubuntu-20.04"
     versions:
       - latest
+      - rapid
+      - 6.0
       - 5.0
       - 4.4
     swift-version: "5.6"
@@ -1363,6 +1494,8 @@ buildvariants:
     swift-version: "5.6"
     versions:
       - latest
+      - rapid
+      - 6.0
       - 5.0
       - 4.4
   display_name: "OCSP ${swift-version} ${os-fully-featured} ${versions}"
@@ -1382,6 +1515,9 @@ buildvariants:
   tasks:
     # Versioned API was introduced in MongoDB 4.7
     - "test-latest-standalone"
+    - "test-rapid-standalone"
+    - "test-6.0-standalone"
+    - "test-5.0-standalone"
 
 - matrix_name: "format-lint"
   display_name: "Format and Lint"
@@ -1418,4 +1554,4 @@ buildvariants:
     ssl-auth: "*"
     check-leaks: "leaks"
   tasks:
-     - ".5.0"
+     - ".6.0 !.load-balancer"
diff --git a/.evergreen/configure-swift.sh b/.evergreen/configure-swift.sh
index c36bc53ef..919b90991 100644
--- a/.evergreen/configure-swift.sh
+++ b/.evergreen/configure-swift.sh
@@ -16,20 +16,16 @@ export SWIFTENV_ROOT="${INSTALL_DIR}/swiftenv"
 export PATH="${SWIFTENV_ROOT}/bin:$PATH"
 eval "$(swiftenv init -)"
 
-# dynamically determine latest available snapshot if needed
-if [ "$SWIFT_VERSION" = "main-snapshot" ]; then
-    SWIFT_VERSION=$(swiftenv install --list-snapshots | tail -1)
-fi
-
 if [ "$OS" == "darwin" ]; then
-    # latest snapshots require a newer version of Xcode/Command Line Tools
-    if [[ "$SWIFT_VERSION" == DEVELOPMENT-SNAPSHOT* ]]; then
-        sudo xcode-select -s /Applications/Xcode13.1.app
+    # 5.2 requires an older version of Xcode/Command Line Tools
+    if [[ "$SWIFT_VERSION" == 5.2.* ]]; then
+        sudo xcode-select -s /Applications/Xcode11.3.app
     else
-        sudo xcode-select -s /Applications/Xcode12.app
+        sudo xcode-select -s /Applications/Xcode13.2.1.app
     fi
 
-    # TODO SWIFT-1421: remove this once we have new Xcode on Evergreen to test with
+    # required to use the toolchain's concurrency library rather than the one which ships with Xcode
+    # and may not necessarily match the Swift version being used.
     export DYLD_LIBRARY_PATH=${SWIFTENV_ROOT}/versions/${SWIFT_VERSION}/usr/lib/swift/macosx/
 fi
 
diff --git a/.evergreen/get_latest_swift_patch.py b/.evergreen/get_latest_swift_patch.py
index ffa32f5a8..450009164 100644
--- a/.evergreen/get_latest_swift_patch.py
+++ b/.evergreen/get_latest_swift_patch.py
@@ -2,33 +2,43 @@
 import requests
 import sys
 
-# This script accepts a version number in the form "x.y" as an argument. It will query the Swift Github
-# repo for releases and find the latest x.y.z patch release if available, and print out the matching tag.
+# This script accepts a single argument which can be either:
+# 1) a version number in the form "x.y", or 
+# 2) the string "snapshot"
+# If a version number is provided the script will query the Swift GitHub repo for releases and find the latest x.y.z patch
+# release if available, and print out the matching tag.
+# If "main-snapshot" is provided the script will find the latest development snapshot tagged on the Swift GitHub repo.
 
 if len(sys.argv) != 2:
     print("Expected 1 argument, but got: {}".format(sys.argv[1:]))
     exit(1)
 
 version = sys.argv[1]
-components = version.split('.')
-if len(components) != 2:
-    print("Expected version number in form x.y, got {}".format(version))
-    exit(1)
 
-major = components[0]
-minor = components[1]
+if version == "main-snapshot":
+    tag_data = requests.get('https://api.github.com/repos/apple/swift/tags').json()
+    latest_snapshot = next(filter(lambda tag: 'swift-DEVELOPMENT-SNAPSHOT' in tag['name'], tag_data))
+    print(latest_snapshot['name'][6:]) # drop the preceding 'swift-' from the tag, because swiftenv does the same when installing it.
+else:
+    components = version.split('.')
+    if len(components) != 2:
+        print("Expected version number in form x.y, got {}".format(version))
+        exit(1)
+
+    major = components[0]
+    minor = components[1]
 
-version_regex = '^swift-({}\.{}(\.(\d+))?)-RELEASE$'.format(major, minor)
+    version_regex = '^swift-({}\.{}(\.(\d+))?)-RELEASE$'.format(major, minor)
 
-release_data = requests.get('https://api.github.com/repos/apple/swift/releases').json()
-tag_names = map(lambda release: release['tag_name'], release_data)
+    release_data = requests.get('https://api.github.com/repos/apple/swift/releases').json()
+    tag_names = map(lambda release: release['tag_name'], release_data)
 
-# find tags matching the specified regexes
-matches = filter(lambda match: match is not None, map(lambda tag: re.match(version_regex, tag), tag_names))
+    # find tags matching the specified regexes
+    matches = filter(lambda match: match is not None, map(lambda tag: re.match(version_regex, tag), tag_names))
 
-# sort matches by their patch versions. patch versions of 0 are omitted so substitute 0 when the group is None.
-sorted_matches = sorted(matches, key=lambda match: int(match.group(2)[1:]) if match.group(2) is not None else 0, reverse=True)
+    # sort matches by their patch versions. patch versions of 0 are omitted so substitute 0 when the group is None.
+    sorted_matches = sorted(matches, key=lambda match: int(match.group(2)[1:]) if match.group(2) is not None else 0, reverse=True)
 
-# map to the first match group which contains the full version number.
-sorted_version_numbers = map(lambda match: match.group(1), sorted_matches)
-print(next(sorted_version_numbers))
+    # map to the first match group which contains the full version number.
+    sorted_version_numbers = map(lambda match: match.group(1), sorted_matches)
+    print(next(sorted_version_numbers))
diff --git a/.evergreen/install-swift.sh b/.evergreen/install-swift.sh
index b69b44796..322f3db95 100644
--- a/.evergreen/install-swift.sh
+++ b/.evergreen/install-swift.sh
@@ -20,8 +20,4 @@ git clone --depth 1 -b "osx-install-path" https://github.com/kmahar/swiftenv.git
 # install swift
 eval "$(swiftenv init -)"
 
-if [ "$SWIFT_VERSION" = "main-snapshot" ]; then
-    SWIFT_VERSION=$(swiftenv install --list-snapshots | tail -1)
-fi
-
 swiftenv install --install-local $SWIFT_VERSION
diff --git a/.evergreen/install-tools.sh b/.evergreen/install-tools.sh
index 164b5aeda..2d26e3a67 100644
--- a/.evergreen/install-tools.sh
+++ b/.evergreen/install-tools.sh
@@ -35,10 +35,10 @@ install_from_gh () {
 
 if [ $1 == "swiftlint" ]
 then
-    build_from_gh swiftlint https://github.com/realm/SwiftLint "0.46.3"
+    build_from_gh swiftlint https://github.com/realm/SwiftLint "0.48.0"
 elif [ $1 == "swiftformat" ]
 then
-    build_from_gh swiftformat https://github.com/nicklockwood/SwiftFormat "0.49.4"
+    build_from_gh swiftformat https://github.com/nicklockwood/SwiftFormat "0.49.17"
 elif [ $1 == "sourcery" ]
 then
     install_from_gh sourcery https://github.com/krzysztofzablocki/Sourcery/releases/download/1.6.1/Sourcery-1.6.1.zip
diff --git a/.evergreen/run-atlas-tests.sh b/.evergreen/run-atlas-tests.sh
index e766741f7..fac792a5b 100755
--- a/.evergreen/run-atlas-tests.sh
+++ b/.evergreen/run-atlas-tests.sh
@@ -9,6 +9,13 @@ INSTALL_DIR="${PROJECT_DIRECTORY}/opt"
 # configure Swift
 . ${PROJECT_DIRECTORY}/.evergreen/configure-swift.sh
 
+
+# work around https://github.com/mattgallagher/CwlPreconditionTesting/issues/22 (bug still exists in version 1.x
+# when using Xcode 13.2)
+if [ "$OS" == "darwin" ]; then
+    EXTRA_FLAGS="-Xswiftc -Xfrontend -Xswiftc -validate-tbd-against-ir=none"
+fi
+
 # run the tests
 ATLAS_REPL="$ATLAS_REPL" ATLAS_SHRD="$ATLAS_SHRD" ATLAS_FREE="$ATLAS_FREE" ATLAS_TLS11="$ATLAS_TLS11" ATLAS_TLS12="$ATLAS_TLS12" \
 ATLAS_REPL_SRV="$ATLAS_REPL_SRV" ATLAS_SHRD_SRV="$ATLAS_SHRD_SRV" ATLAS_FREE_SRV="$ATLAS_FREE_SRV" ATLAS_TLS11_SRV="$ATLAS_TLS11_SRV" ATLAS_TLS12_SRV="$ATLAS_TLS12_SRV" \
diff --git a/.evergreen/run-ocsp-test.sh b/.evergreen/run-ocsp-test.sh
index 1afbcbc08..e8dd249f3 100644
--- a/.evergreen/run-ocsp-test.sh
+++ b/.evergreen/run-ocsp-test.sh
@@ -29,11 +29,18 @@ INSTALL_DIR="${PROJECT_DIRECTORY}/opt"
 # configure Swift
 . ${PROJECT_DIRECTORY}/.evergreen/configure-swift.sh
 
+
+# work around https://github.com/mattgallagher/CwlPreconditionTesting/issues/22 (bug still exists in version 1.x
+# when using Xcode 13.2)
+if [ "$OS" == "darwin" ]; then
+    EXTRA_FLAGS="-Xswiftc -Xfrontend -Xswiftc -validate-tbd-against-ir=none"
+fi
+
 # build the driver
-swift build
+swift build $EXTRA_FLAGS
 
 # test the driver
 set +o errexit # even if tests fail we want to parse the results, so disable errexit
 set -o pipefail # propagate error codes in the following pipes
 
-swift test --enable-test-discovery --filter=OCSP
+swift test --enable-test-discovery $EXTRA_FLAGS --filter=OCSP
diff --git a/.evergreen/run-serverless-tests.sh b/.evergreen/run-serverless-tests.sh
index 3858bcb01..b2318805a 100755
--- a/.evergreen/run-serverless-tests.sh
+++ b/.evergreen/run-serverless-tests.sh
@@ -18,8 +18,15 @@ fi
 # configure Swift
 . ${PROJECT_DIRECTORY}/.evergreen/configure-swift.sh
 
+
+# work around https://github.com/mattgallagher/CwlPreconditionTesting/issues/22 (bug still exists in version 1.x
+# when using Xcode 13.2)
+if [ "$OS" == "darwin" ]; then
+    EXTRA_FLAGS="-Xswiftc -Xfrontend -Xswiftc -validate-tbd-against-ir=none"
+fi
+
 # build the driver
-swift build
+swift build $EXTRA_FLAGS
 
 MONGODB_TOPOLOGY="load_balanced" \
   MONGODB_URI=${MONGODB_URI} \
@@ -30,4 +37,4 @@ MONGODB_TOPOLOGY="load_balanced" \
   MONGODB_SCRAM_PASSWORD=${SERVERLESS_ATLAS_PASSWORD} \
   AUTH="auth" \
   SSL="ssl" \
-    swift test --enable-test-discovery --filter="(Crud|Retryable|Transactions|Versioned|Session|LoadBalancer|MongoCursor|Unified)"
+    swift test --enable-test-discovery $EXTRA_FLAGS --filter="(Crud|Retryable|Transactions|Versioned|Session|LoadBalancer|MongoCursor|Unified)"
diff --git a/.evergreen/run-tests.sh b/.evergreen/run-tests.sh
index 272f8e943..29dd34465 100755
--- a/.evergreen/run-tests.sh
+++ b/.evergreen/run-tests.sh
@@ -39,12 +39,10 @@ if [ "$SANITIZE" != "false" ]; then
     SANITIZE_STATEMENT="--sanitize ${SANITIZE}"
 fi
 
-# TODO SWIFT-1421: remove this, it is currently needed due to a bug in Xcode 13.0/13.1.
-# see: https://bugs.swift.org/browse/SR-14968
+# work around https://github.com/mattgallagher/CwlPreconditionTesting/issues/22 (bug still exists in version 1.x
+# when using Xcode 13.2)
 if [ "$OS" == "darwin" ]; then
-    if [[ "$SWIFT_VERSION" == DEVELOPMENT-SNAPSHOT* ]]; then
-        EXTRA_FLAGS="-Xswiftc -Xfrontend -Xswiftc -validate-tbd-against-ir=none"
-    fi
+    EXTRA_FLAGS="-Xswiftc -Xfrontend -Xswiftc -validate-tbd-against-ir=none"
 fi
 
 # build the driver
diff --git a/Package.swift b/Package.swift
index bdf19cc04..9f38497d2 100644
--- a/Package.swift
+++ b/Package.swift
@@ -1,13 +1,4 @@
-// swift-tools-version:5.1
-
-///  To avoid breaking Swift 5.1 compatibility, only require newer NIO versions when we need NIO's concurrency APIs.
-func getMinNIOVersion() -> PackageDescription.Package.Dependency.Requirement {
-#if compiler(>=5.5.2) && canImport(_Concurrency)
-    return .upToNextMajor(from: "2.36.0")
-#else
-    return .upToNextMajor(from: "2.15.0")
-#endif
-}
+// swift-tools-version:5.2
 
 import PackageDescription
 let package = Package(
@@ -20,17 +11,56 @@ let package = Package(
         .library(name: "MongoSwiftSync", targets: ["MongoSwiftSync"])
     ],
     dependencies: [
-        .package(url: "https://github.com/Quick/Nimble.git", .upToNextMajor(from: "8.0.0")),
-        .package(url: "https://github.com/apple/swift-nio", getMinNIOVersion()),
+        .package(url: "https://github.com/Quick/Nimble", .upToNextMajor(from: "8.0.0")),
+        .package(url: "https://github.com/apple/swift-nio", .upToNextMajor(from: "2.36.0")),
         .package(url: "https://github.com/mongodb/swift-bson", .upToNextMajor(from: "3.0.0"))
     ],
     targets: [
-        .target(name: "MongoSwiftSync", dependencies: ["MongoSwift", "NIO"]),
+        .target(
+            name: "MongoSwiftSync",
+            dependencies: [
+                "MongoSwift",
+                .product(name: "NIOPosix", package: "swift-nio"),
+            ]
+        ),
         .target(name: "AtlasConnectivity", dependencies: ["MongoSwiftSync"]),
-        .target(name: "TestsCommon", dependencies: ["MongoSwift", "Nimble"]),
-        .testTarget(name: "BSONTests", dependencies: ["MongoSwift", "TestsCommon", "Nimble", "CLibMongoC"]),
-        .testTarget(name: "MongoSwiftTests", dependencies: ["MongoSwift", "TestsCommon", "Nimble", "NIO", "NIOConcurrencyHelpers"]),
-        .testTarget(name: "MongoSwiftSyncTests", dependencies: ["MongoSwiftSync", "TestsCommon", "Nimble", "MongoSwift"]),
+        .target(
+            name: "TestsCommon",
+            dependencies: [
+                "MongoSwift",
+                .product(name: "Nimble", package: "Nimble"),
+            ]
+        ),
+        .testTarget(
+            name: "BSONTests",
+            dependencies: [
+                "MongoSwift",
+                "TestsCommon",
+                "CLibMongoC",
+                .product(name: "Nimble", package: "Nimble")
+            ]
+        ),
+        .testTarget(
+            name: "MongoSwiftTests",
+            dependencies: [
+                "MongoSwift",
+                "TestsCommon",
+                "Nimble",
+                .product(name: "NIOConcurrencyHelpers", package: "swift-nio"),
+                .product(name: "NIOCore", package: "swift-nio"),
+                .product(name: "NIOPosix", package: "swift-nio")
+            ]
+        ),
+        .testTarget(
+            name: "MongoSwiftSyncTests",
+            dependencies: [
+                "MongoSwiftSync",
+                "TestsCommon",
+                "MongoSwift",
+                .product(name: "NIOConcurrencyHelpers", package: "swift-nio"),
+                .product(name: "Nimble", package: "Nimble")
+            ]
+        ),
         .target(
             name: "CLibMongoC",
             dependencies: [],
@@ -46,7 +76,30 @@ let package = Package(
 
 #if compiler(>=5.3)
 package.dependencies += [.package(url: "https://github.com/apple/swift-atomics", .upToNextMajor(from: "1.0.0"))]
-package.targets += [.target(name: "MongoSwift", dependencies: ["Atomics", "CLibMongoC", "NIO", "NIOConcurrencyHelpers", "SwiftBSON"])]
+package.targets += [
+    .target(
+        name: "MongoSwift",
+        dependencies: [
+            "CLibMongoC",
+            .product(name: "Atomics", package: "swift-atomics"),
+            .product(name: "NIOConcurrencyHelpers", package: "swift-nio"),
+            .product(name: "NIOCore", package: "swift-nio"),
+            .product(name: "NIOPosix", package: "swift-nio"),
+            .product(name: "SwiftBSON", package: "swift-bson")
+        ]
+    )
+]
 #else
-package.targets += [.target(name: "MongoSwift", dependencies: ["CLibMongoC", "NIO", "NIOConcurrencyHelpers", "SwiftBSON"])]
+package.targets += [
+    .target(
+        name: "MongoSwift",
+        dependencies: [
+            "CLibMongoC",
+            .product(name: "NIOConcurrencyHelpers", package: "swift-nio"),
+            .product(name: "NIOCore", package: "swift-nio"),
+            .product(name: "NIOPosix", package: "swift-nio"),
+            .product(name: "SwiftBSON", package: "swift-bson")
+        ]
+    )
+]
 #endif
diff --git a/README.md b/README.md
index 9d190c95e..abc87fbb8 100644
--- a/README.md
+++ b/README.md
@@ -85,7 +85,7 @@ Note: You should call `cleanupMongoSwift()` exactly once at the end of your appl
 **Async/Await (recommended)**:
 ```swift
 import MongoSwift
-import NIO
+import NIOPosix
 
 let elg = MultiThreadedEventLoopGroup(numberOfThreads: 4)
 let client = try MongoClient("mongodb://localhost:27017", using: elg)
@@ -107,7 +107,7 @@ let collection = try await db.createCollection("myCollection")
 **Async (`EventLoopFuture`s)**:
 ```swift
 import MongoSwift
-import NIO
+import NIOPosix
 
 let elg = MultiThreadedEventLoopGroup(numberOfThreads: 4)
 let client = try MongoClient("mongodb://localhost:27017", using: elg)
diff --git a/Sources/MongoSwift/BSON/BSONPointerUtils.swift b/Sources/MongoSwift/BSON/BSONPointerUtils.swift
index 773d6f0e7..4a2ede3d4 100644
--- a/Sources/MongoSwift/BSON/BSONPointerUtils.swift
+++ b/Sources/MongoSwift/BSON/BSONPointerUtils.swift
@@ -1,6 +1,6 @@
 import CLibMongoC
 import Foundation
-import NIO
+import NIOCore
 
 internal typealias BSONPointer = UnsafePointer<bson_t>
 internal typealias MutableBSONPointer = UnsafeMutablePointer<bson_t>
diff --git a/Sources/MongoSwift/ChangeStream.swift b/Sources/MongoSwift/ChangeStream.swift
index ad683cedc..c9c07d2d7 100644
--- a/Sources/MongoSwift/ChangeStream.swift
+++ b/Sources/MongoSwift/ChangeStream.swift
@@ -1,6 +1,6 @@
 import CLibMongoC
 import Foundation
-import NIO
+import NIOCore
 
 /// Direct wrapper of a `mongoc_change_stream_t`.
 private struct MongocChangeStream: MongocCursorWrapper {
diff --git a/Sources/MongoSwift/ClientSession.swift b/Sources/MongoSwift/ClientSession.swift
index b387bc322..50a6ffdb1 100644
--- a/Sources/MongoSwift/ClientSession.swift
+++ b/Sources/MongoSwift/ClientSession.swift
@@ -1,6 +1,6 @@
 import CLibMongoC
 import Foundation
-import NIO
+import NIOCore
 
 // sourcery: skipSyncExport
 /**
diff --git a/Sources/MongoSwift/ConnectionPool.swift b/Sources/MongoSwift/ConnectionPool.swift
index 99e33a941..4014ee76f 100644
--- a/Sources/MongoSwift/ConnectionPool.swift
+++ b/Sources/MongoSwift/ConnectionPool.swift
@@ -1,7 +1,7 @@
 import CLibMongoC
 import Foundation
-import NIO
 import NIOConcurrencyHelpers
+import NIOCore
 import SwiftBSON
 
 /// A connection to the database.
diff --git a/Sources/MongoSwift/CursorCommon.swift b/Sources/MongoSwift/CursorCommon.swift
index c0c68b9dd..e6019513e 100644
--- a/Sources/MongoSwift/CursorCommon.swift
+++ b/Sources/MongoSwift/CursorCommon.swift
@@ -1,7 +1,7 @@
 import CLibMongoC
 import Foundation
-import NIO
 import NIOConcurrencyHelpers
+import NIOCore
 
 /// A protocol describing the common public API between cursor-like objects in the driver.
 internal protocol CursorProtocol {
diff --git a/Sources/MongoSwift/EventLoopBoundMongoClient.swift b/Sources/MongoSwift/EventLoopBoundMongoClient.swift
index 8fecb475d..052827ecd 100644
--- a/Sources/MongoSwift/EventLoopBoundMongoClient.swift
+++ b/Sources/MongoSwift/EventLoopBoundMongoClient.swift
@@ -1,4 +1,4 @@
-import NIO
+import NIOCore
 
 // sourcery: skipSyncExport
 /// A wrapper around a `MongoClient` that will return `EventLoopFuture`s on the specified `EventLoop`.
diff --git a/Sources/MongoSwift/MongoClient.swift b/Sources/MongoSwift/MongoClient.swift
index 5a7f1a0e7..abf1727b1 100644
--- a/Sources/MongoSwift/MongoClient.swift
+++ b/Sources/MongoSwift/MongoClient.swift
@@ -1,7 +1,7 @@
 import CLibMongoC
 import Foundation
-import NIO
 import NIOConcurrencyHelpers
+import NIOCore
 
 /// Options to use when creating a `MongoClient`.
 public struct MongoClientOptions: CodingStrategyProvider {
diff --git a/Sources/MongoSwift/MongoCollection+BulkWrite.swift b/Sources/MongoSwift/MongoCollection+BulkWrite.swift
index b9a1545f4..3fa456598 100644
--- a/Sources/MongoSwift/MongoCollection+BulkWrite.swift
+++ b/Sources/MongoSwift/MongoCollection+BulkWrite.swift
@@ -1,5 +1,5 @@
 import CLibMongoC
-import NIO
+import NIOCore
 
 /// An extension of `MongoCollection` encapsulating bulk write operations.
 extension MongoCollection {
diff --git a/Sources/MongoSwift/MongoCollection+ChangeStreams.swift b/Sources/MongoSwift/MongoCollection+ChangeStreams.swift
index a194ab809..0effa59f8 100644
--- a/Sources/MongoSwift/MongoCollection+ChangeStreams.swift
+++ b/Sources/MongoSwift/MongoCollection+ChangeStreams.swift
@@ -1,5 +1,5 @@
 import CLibMongoC
-import NIO
+import NIOCore
 
 extension MongoCollection {
     /**
diff --git a/Sources/MongoSwift/MongoCollection+FindAndModify.swift b/Sources/MongoSwift/MongoCollection+FindAndModify.swift
index 49f763e81..c33c1ff7d 100644
--- a/Sources/MongoSwift/MongoCollection+FindAndModify.swift
+++ b/Sources/MongoSwift/MongoCollection+FindAndModify.swift
@@ -1,5 +1,5 @@
 import CLibMongoC
-import NIO
+import NIOCore
 
 /// An extension of `MongoCollection` encapsulating find and modify operations.
 extension MongoCollection {
diff --git a/Sources/MongoSwift/MongoCollection+Indexes.swift b/Sources/MongoSwift/MongoCollection+Indexes.swift
index 9335aca11..457531d9b 100644
--- a/Sources/MongoSwift/MongoCollection+Indexes.swift
+++ b/Sources/MongoSwift/MongoCollection+Indexes.swift
@@ -1,5 +1,5 @@
 import CLibMongoC
-import NIO
+import NIOCore
 
 /// A struct representing an index on a `MongoCollection`.
 public struct IndexModel: Codable {
diff --git a/Sources/MongoSwift/MongoCollection+Read.swift b/Sources/MongoSwift/MongoCollection+Read.swift
index 5790b219c..236c4192e 100644
--- a/Sources/MongoSwift/MongoCollection+Read.swift
+++ b/Sources/MongoSwift/MongoCollection+Read.swift
@@ -1,5 +1,5 @@
 import CLibMongoC
-import NIO
+import NIOCore
 
 /// An extension of `MongoCollection` encapsulating read operations.
 extension MongoCollection {
diff --git a/Sources/MongoSwift/MongoCollection+Write.swift b/Sources/MongoSwift/MongoCollection+Write.swift
index a3eac4cdf..2cbe2fdb0 100644
--- a/Sources/MongoSwift/MongoCollection+Write.swift
+++ b/Sources/MongoSwift/MongoCollection+Write.swift
@@ -1,5 +1,5 @@
 import CLibMongoC
-import NIO
+import NIOCore
 import SwiftBSON
 
 /// An extension of `MongoCollection` encapsulating write operations.
diff --git a/Sources/MongoSwift/MongoCollection.swift b/Sources/MongoSwift/MongoCollection.swift
index 9d79c23b7..1d8e7750a 100644
--- a/Sources/MongoSwift/MongoCollection.swift
+++ b/Sources/MongoSwift/MongoCollection.swift
@@ -1,5 +1,5 @@
 import CLibMongoC
-import NIO
+import NIOCore
 
 /// Options to use when dropping a collection.
 public struct DropCollectionOptions: Codable {
diff --git a/Sources/MongoSwift/MongoConnectionString.swift b/Sources/MongoSwift/MongoConnectionString.swift
index 904ce2b9b..860454d22 100644
--- a/Sources/MongoSwift/MongoConnectionString.swift
+++ b/Sources/MongoSwift/MongoConnectionString.swift
@@ -467,12 +467,10 @@ public struct MongoConnectionString: Codable, LosslessStringConvertible {
         // Parse the defaultAuthDB if present.
         if userHostsAndAuthDB.count == 2 && !userHostsAndAuthDB[1].isEmpty {
             let defaultAuthDB = try userHostsAndAuthDB[1].getPercentDecoded(forKey: "defaultAuthDB")
-            for character in Self.forbiddenDBCharacters {
-                if defaultAuthDB.contains(character) {
-                    throw MongoError.InvalidArgumentError(
-                        message: "defaultAuthDB contains invalid character: \(character)"
-                    )
-                }
+            for character in Self.forbiddenDBCharacters where defaultAuthDB.contains(character) {
+                throw MongoError.InvalidArgumentError(
+                    message: "defaultAuthDB contains invalid character: \(character)"
+                )
             }
             self.defaultAuthDB = defaultAuthDB
             // If no other authentication options were provided, we should use the defaultAuthDB as the credential
@@ -1347,13 +1345,11 @@ extension StringProtocol {
     }
 
     fileprivate func getValidatedUserInfo(forKey key: String) throws -> String {
-        for character in MongoConnectionString.genDelims {
-            if self.contains(character) {
-                throw MongoError.InvalidArgumentError(
-                    message: "\(key) in the connection string contains invalid character that must be percent-encoded:"
-                        + " \(character)"
-                )
-            }
+        for character in MongoConnectionString.genDelims where self.contains(character) {
+            throw MongoError.InvalidArgumentError(
+                message: "\(key) in the connection string contains invalid character that must be percent-encoded:"
+                    + " \(character)"
+            )
         }
         return try self.getPercentDecoded(forKey: key)
     }
diff --git a/Sources/MongoSwift/MongoCursor.swift b/Sources/MongoSwift/MongoCursor.swift
index 49957c7c1..d809f8249 100644
--- a/Sources/MongoSwift/MongoCursor.swift
+++ b/Sources/MongoSwift/MongoCursor.swift
@@ -1,7 +1,7 @@
 import CLibMongoC
 import Foundation
-import NIO
 import NIOConcurrencyHelpers
+import NIOCore
 
 /// Direct wrapper of a `mongoc_cursor_t`.
 internal struct MongocCursor: MongocCursorWrapper {
diff --git a/Sources/MongoSwift/MongoDatabase.swift b/Sources/MongoSwift/MongoDatabase.swift
index ac02a85c7..e97ddec62 100644
--- a/Sources/MongoSwift/MongoDatabase.swift
+++ b/Sources/MongoSwift/MongoDatabase.swift
@@ -1,5 +1,5 @@
 import CLibMongoC
-import NIO
+import NIOCore
 
 /// Options to set on a retrieved `MongoCollection`.
 public struct MongoCollectionOptions: CodingStrategyProvider {
diff --git a/Sources/MongoSwift/Operations/AggregateOperation.swift b/Sources/MongoSwift/Operations/AggregateOperation.swift
index a89488b0b..76319b78f 100644
--- a/Sources/MongoSwift/Operations/AggregateOperation.swift
+++ b/Sources/MongoSwift/Operations/AggregateOperation.swift
@@ -1,6 +1,6 @@
 import CLibMongoC
 import Foundation
-import NIO
+import NIOCore
 
 /// The entity on which to execute the `aggregate` command against.
 internal enum AggregateTarget<CollectionType: Codable> {
diff --git a/Sources/MongoSwift/Operations/Operation.swift b/Sources/MongoSwift/Operations/Operation.swift
index 9a8670947..a149b4bc7 100644
--- a/Sources/MongoSwift/Operations/Operation.swift
+++ b/Sources/MongoSwift/Operations/Operation.swift
@@ -1,4 +1,5 @@
-import NIO
+import NIOCore
+import NIOPosix
 
 /// A protocol for operation types to conform to. An `Operation` instance corresponds to any single operation a user
 /// can perform with the driver's API that requires I/O.
diff --git a/Sources/MongoSwift/Operations/WatchOperation.swift b/Sources/MongoSwift/Operations/WatchOperation.swift
index 23bdcb61c..c811172cc 100644
--- a/Sources/MongoSwift/Operations/WatchOperation.swift
+++ b/Sources/MongoSwift/Operations/WatchOperation.swift
@@ -1,5 +1,5 @@
 import CLibMongoC
-import NIO
+import NIOCore
 
 /// The entity on which to start a change stream.
 internal enum ChangeStreamTarget<CollectionType: Codable> {
diff --git a/Sources/MongoSwiftSync/MongoClient.swift b/Sources/MongoSwiftSync/MongoClient.swift
index ece557b90..7a69d7f53 100644
--- a/Sources/MongoSwiftSync/MongoClient.swift
+++ b/Sources/MongoSwiftSync/MongoClient.swift
@@ -1,5 +1,5 @@
 import MongoSwift
-import NIO
+import NIOPosix
 
 /// A MongoDB Client providing a synchronous API.
 public class MongoClient {
diff --git a/Sources/TestsCommon/SpecTestUtils.swift b/Sources/TestsCommon/SpecTestUtils.swift
index 0d609d8d7..bb91c21df 100644
--- a/Sources/TestsCommon/SpecTestUtils.swift
+++ b/Sources/TestsCommon/SpecTestUtils.swift
@@ -1,6 +1,5 @@
 import Foundation
-@testable import MongoSwift
-import NIO
+import MongoSwift
 import XCTest
 
 extension MongoSwiftTestCase {
diff --git a/Tests/LinuxMain.swift b/Tests/LinuxMain.swift
index d36faa1b0..c406ddfe2 100644
--- a/Tests/LinuxMain.swift
+++ b/Tests/LinuxMain.swift
@@ -1 +1 @@
-// This is a placeholder file which is required for compilation on Swift 5.1.
+// This is a placeholder file which is required for compilation on Swift 5.2.
diff --git a/Tests/MongoSwiftSyncTests/UnifiedTestRunner/UnifiedTestRunner.swift b/Tests/MongoSwiftSyncTests/UnifiedTestRunner/UnifiedTestRunner.swift
index eb0689565..cab7b21c7 100644
--- a/Tests/MongoSwiftSyncTests/UnifiedTestRunner/UnifiedTestRunner.swift
+++ b/Tests/MongoSwiftSyncTests/UnifiedTestRunner/UnifiedTestRunner.swift
@@ -183,9 +183,13 @@ struct UnifiedTestRunner {
                     let collEntities = context.entities.values.compactMap { try? $0.asCollection() }
                     for (_, client) in try self.internalClient.asMongosClients() {
                         for entity in collEntities {
-                            _ = try client.db(entity.namespace.db).runCommand(
-                                ["distinct": .string(entity.name), "key": "_id"]
-                            )
+                            do {
+                                _ = try client.db(entity.namespace.db).runCommand(
+                                    ["distinct": .string(entity.name), "key": "_id"]
+                                )
+                            } catch let commandError as MongoError.CommandError where commandError.code == 26 {
+                                // ignore NamespaceNotFound errors from distinct.
+                            }
                         }
                     }
                 }
diff --git a/Tests/MongoSwiftTests/APMTests.swift b/Tests/MongoSwiftTests/APMTests.swift
index e481a5eac..784687020 100644
--- a/Tests/MongoSwiftTests/APMTests.swift
+++ b/Tests/MongoSwiftTests/APMTests.swift
@@ -1,8 +1,8 @@
 #if compiler(>=5.5.2) && canImport(_Concurrency)
 import MongoSwift
 import Nimble
-import NIO
 import NIOConcurrencyHelpers
+import NIOPosix
 import TestsCommon
 
 private protocol StreamableEvent {
@@ -177,10 +177,8 @@ final class APMTests: MongoSwiftTestCase {
             let sdamTask = Task { () -> [EventType] in
                 var eventTypeSdam: [EventType] = []
                 taskStarted.store(true)
-                for try await event in client.sdamEventStream() {
-                    if !event.isHeartbeatEvent {
-                        eventTypeSdam.append(event.type)
-                    }
+                for try await event in client.sdamEventStream() where !event.isHeartbeatEvent {
+                    eventTypeSdam.append(event.type)
                 }
                 return eventTypeSdam
             }
diff --git a/Tests/MongoSwiftTests/AsyncAwaitTestUtils.swift b/Tests/MongoSwiftTests/AsyncAwaitTestUtils.swift
index 8138b1461..aad816722 100644
--- a/Tests/MongoSwiftTests/AsyncAwaitTestUtils.swift
+++ b/Tests/MongoSwiftTests/AsyncAwaitTestUtils.swift
@@ -2,7 +2,8 @@
 
 import Foundation
 import MongoSwift
-import NIO
+import NIOCore
+import NIOPosix
 import TestsCommon
 import XCTest
 
diff --git a/Tests/MongoSwiftTests/AsyncAwaitTests.swift b/Tests/MongoSwiftTests/AsyncAwaitTests.swift
index 01a1f750a..d421f6411 100644
--- a/Tests/MongoSwiftTests/AsyncAwaitTests.swift
+++ b/Tests/MongoSwiftTests/AsyncAwaitTests.swift
@@ -3,8 +3,9 @@
 import Foundation
 @testable import MongoSwift
 import Nimble
-import NIO
 import NIOConcurrencyHelpers
+import NIOCore
+import NIOPosix
 import TestsCommon
 import XCTest
 
diff --git a/Tests/MongoSwiftTests/AsyncTestUtils.swift b/Tests/MongoSwiftTests/AsyncTestUtils.swift
index 67ce2e5b7..ce4f350a9 100644
--- a/Tests/MongoSwiftTests/AsyncTestUtils.swift
+++ b/Tests/MongoSwiftTests/AsyncTestUtils.swift
@@ -1,6 +1,7 @@
 import Foundation
 import MongoSwift
-import NIO
+import NIOCore
+import NIOPosix
 import TestsCommon
 import XCTest
 
diff --git a/Tests/MongoSwiftTests/ChangeStreamTests.swift b/Tests/MongoSwiftTests/ChangeStreamTests.swift
index a7e0a57f6..e6bc02c16 100644
--- a/Tests/MongoSwiftTests/ChangeStreamTests.swift
+++ b/Tests/MongoSwiftTests/ChangeStreamTests.swift
@@ -1,7 +1,6 @@
 import Foundation
 import MongoSwift
 import Nimble
-import NIO
 import NIOConcurrencyHelpers
 import TestsCommon
 
diff --git a/Tests/MongoSwiftTests/ClientSessionTests.swift b/Tests/MongoSwiftTests/ClientSessionTests.swift
index 1eca4c65d..a92bfbc56 100644
--- a/Tests/MongoSwiftTests/ClientSessionTests.swift
+++ b/Tests/MongoSwiftTests/ClientSessionTests.swift
@@ -1,6 +1,6 @@
 @testable import MongoSwift
 import Nimble
-import NIO
+import NIOCore
 import TestsCommon
 
 final class ClientSessionTests: MongoSwiftTestCase {
diff --git a/Tests/MongoSwiftTests/EventLoopBoundMongoClientTests.swift b/Tests/MongoSwiftTests/EventLoopBoundMongoClientTests.swift
index 100dc7064..b7ca6ed6f 100644
--- a/Tests/MongoSwiftTests/EventLoopBoundMongoClientTests.swift
+++ b/Tests/MongoSwiftTests/EventLoopBoundMongoClientTests.swift
@@ -1,6 +1,6 @@
 @testable import MongoSwift
 import Nimble
-import NIO
+import NIOPosix
 import TestsCommon
 
 final class EventLoopBoundMongoClientTests: MongoSwiftTestCase {
@@ -320,7 +320,7 @@ final class EventLoopBoundMongoClientTests: MongoSwiftTestCase {
             defer { try? db.drop().wait() }
 
             let wrongEventLoop = MultiThreadedEventLoopGroup(numberOfThreads: 4).next()
-            let withSessionFuture: EventLoopFuture<[String]> = elBoundClient.withSession { session in
+            let withSessionFuture = elBoundClient.withSession { session in
                 db.listCollectionNames(session: session).hop(to: wrongEventLoop)
             }
             expect(withSessionFuture.eventLoop) === expectedEventLoop
diff --git a/Tests/MongoSwiftTests/MongoClientTests.swift b/Tests/MongoSwiftTests/MongoClientTests.swift
index 1f34e81da..7536ea088 100644
--- a/Tests/MongoSwiftTests/MongoClientTests.swift
+++ b/Tests/MongoSwiftTests/MongoClientTests.swift
@@ -1,7 +1,7 @@
 import Foundation
 @testable import MongoSwift
 import Nimble
-import NIO
+import NIOPosix
 import TestsCommon
 
 final class MongoClientTests: MongoSwiftTestCase {
diff --git a/Tests/MongoSwiftTests/MongoCursorTests.swift b/Tests/MongoSwiftTests/MongoCursorTests.swift
index cab74cace..8363eff98 100644
--- a/Tests/MongoSwiftTests/MongoCursorTests.swift
+++ b/Tests/MongoSwiftTests/MongoCursorTests.swift
@@ -1,7 +1,6 @@
 import Foundation
 @testable import MongoSwift
 import Nimble
-import NIO
 import NIOConcurrencyHelpers
 import TestsCommon
 
diff --git a/Tests/MongoSwiftTests/ReadWriteConcernSpecTests.swift b/Tests/MongoSwiftTests/ReadWriteConcernSpecTests.swift
index 3dba671f2..967cdd550 100644
--- a/Tests/MongoSwiftTests/ReadWriteConcernSpecTests.swift
+++ b/Tests/MongoSwiftTests/ReadWriteConcernSpecTests.swift
@@ -1,6 +1,6 @@
 import MongoSwift
 import Nimble
-import NIO
+import NIOPosix
 import TestsCommon
 
 extension WriteConcern {
diff --git a/Tests/MongoSwiftTests/ServerSelectionTests.swift b/Tests/MongoSwiftTests/ServerSelectionTests.swift
index 21c6bf673..dd72a98e1 100644
--- a/Tests/MongoSwiftTests/ServerSelectionTests.swift
+++ b/Tests/MongoSwiftTests/ServerSelectionTests.swift
@@ -2,7 +2,6 @@
 import Foundation
 @testable import MongoSwift
 import Nimble
-import NIO
 import TestsCommon
 import XCTest