diff --git a/.evergreen/config/build-task-groups.yml b/.evergreen/config/build-task-groups.yml
index f11b32843..f01c93bf8 100644
--- a/.evergreen/config/build-task-groups.yml
+++ b/.evergreen/config/build-task-groups.yml
@@ -32,7 +32,7 @@ task_groups:
 
   - name: "build-php-libmongoc"
     # Keep this in sync with the actual number of libmongoc builds (typically 3) defined in _template-build-libmongoc.yml
-    max_hosts: 4
+    max_hosts: 2
     setup_task: *build_setup
     setup_task_can_fail_task: true
     setup_task_timeout_secs: 1800
diff --git a/.evergreen/config/generated/build/build-libmongoc.yml b/.evergreen/config/generated/build/build-libmongoc.yml
index 5338fd4c3..7317e94e6 100644
--- a/.evergreen/config/generated/build/build-libmongoc.yml
+++ b/.evergreen/config/generated/build/build-libmongoc.yml
@@ -12,7 +12,7 @@ tasks:
       - func: "compile driver"
         vars:
           PHP_VERSION: "8.3"
-          LIBMONGOC_VERSION: "1.28.0"
+          LIBMONGOC_VERSION: "1.28.1"
       - func: "upload build"
 
   - name: "build-php-8.3-libmongoc-next-stable"
@@ -24,11 +24,13 @@ tasks:
           LIBMONGOC_VERSION: "r1.28"
       - func: "upload build"
 
-  - name: "build-php-8.3-libmongoc-latest"
-    tags: ["build-libmongoc", "php8.3"]
-    commands:
-      - func: "compile driver"
-        vars:
-          PHP_VERSION: "8.3"
-          LIBMONGOC_VERSION: "master"
-      - func: "upload build"
+# TODO: this currently fails as libmongoc master needs changes to build directories
+# We can re-enable this after switching to 1.29-dev
+#  - name: "build-php-8.3-libmongoc-latest"
+#    tags: ["build-libmongoc", "php8.3"]
+#    commands:
+#      - func: "compile driver"
+#        vars:
+#          PHP_VERSION: "8.3"
+#          LIBMONGOC_VERSION: "master"
+#      - func: "upload build"
diff --git a/.evergreen/config/generated/test-variant/libmongoc.yml b/.evergreen/config/generated/test-variant/libmongoc.yml
index 85b41e617..c7c9db90a 100644
--- a/.evergreen/config/generated/test-variant/libmongoc.yml
+++ b/.evergreen/config/generated/test-variant/libmongoc.yml
@@ -63,33 +63,33 @@ buildvariants:
         execution_tasks:
           - ".ocsp .7.0"
 
-  - name: test-debian12-php-8.3-libmongoc-latest
-    tags: ["test", "libmongoc", "debian", "x64", "php8.3"]
-    display_name: "Test: Debian 12, PHP 8.3, libmongoc latest"
-    run_on: debian12-small
-    expansions:
-      FETCH_BUILD_VARIANT: "build-debian12"
-      FETCH_BUILD_TASK: "build-php-8.3-libmongoc-latest"
-    depends_on:
-      - variant: "build-debian12"
-        name: "build-php-8.3-libmongoc-latest"
-    tasks:
-      - ".standalone .local !.4.0 !.4.2 !.4.4 !.5.0 !.6.0"
-      - ".replicaset .local !.4.0 !.4.2 !.4.4 !.5.0 !.6.0"
-      - ".sharded .local !.4.0 !.4.2 !.4.4 !.5.0 !.6.0"
-      - ".loadbalanced .local !.4.0 !.4.2 !.4.4 !.5.0 !.6.0"
-      - "test-atlas-connectivity"
-      - ".ocsp !.4.4 !.5.0 !.6.0"
-    display_tasks:
-      - name: "test-ocsp-latest"
-        execution_tasks:
-          - ".ocsp .latest"
-      - name: "test-ocsp-rapid"
-        execution_tasks:
-          - ".ocsp .rapid"
-      - name: "test-ocsp-8.0"
-        execution_tasks:
-          - ".ocsp .8.0"
-      - name: "test-ocsp-7.0"
-        execution_tasks:
-          - ".ocsp .7.0"
+#  - name: test-debian12-php-8.3-libmongoc-latest
+#    tags: ["test", "libmongoc", "debian", "x64", "php8.3"]
+#    display_name: "Test: Debian 12, PHP 8.3, libmongoc latest"
+#    run_on: debian12-small
+#    expansions:
+#      FETCH_BUILD_VARIANT: "build-debian12"
+#      FETCH_BUILD_TASK: "build-php-8.3-libmongoc-latest"
+#    depends_on:
+#      - variant: "build-debian12"
+#        name: "build-php-8.3-libmongoc-latest"
+#    tasks:
+#      - ".standalone .local !.4.0 !.4.2 !.4.4 !.5.0 !.6.0"
+#      - ".replicaset .local !.4.0 !.4.2 !.4.4 !.5.0 !.6.0"
+#      - ".sharded .local !.4.0 !.4.2 !.4.4 !.5.0 !.6.0"
+#      - ".loadbalanced .local !.4.0 !.4.2 !.4.4 !.5.0 !.6.0"
+#      - "test-atlas-connectivity"
+#      - ".ocsp !.4.4 !.5.0 !.6.0"
+#    display_tasks:
+#      - name: "test-ocsp-latest"
+#        execution_tasks:
+#          - ".ocsp .latest"
+#      - name: "test-ocsp-rapid"
+#        execution_tasks:
+#          - ".ocsp .rapid"
+#      - name: "test-ocsp-8.0"
+#        execution_tasks:
+#          - ".ocsp .8.0"
+#      - name: "test-ocsp-7.0"
+#        execution_tasks:
+#          - ".ocsp .7.0"
diff --git a/.evergreen/config/generated/test-variant/php-full.yml b/.evergreen/config/generated/test-variant/php-full.yml
index fd32527cc..b922689e5 100644
--- a/.evergreen/config/generated/test-variant/php-full.yml
+++ b/.evergreen/config/generated/test-variant/php-full.yml
@@ -74,7 +74,6 @@ buildvariants:
       - ".standalone .local !.5.0 !.6.0 !.7.0 !.8.0 !.rapid !.latest"
       - ".replicaset .local !.5.0 !.6.0 !.7.0 !.8.0 !.rapid !.latest"
       - ".sharded .local !.5.0 !.6.0 !.7.0 !.8.0 !.rapid !.latest"
-      - ".loadbalanced .local !.5.0 !.6.0 !.7.0 !.8.0 !.rapid !.latest"
       - ".ocsp !.5.0 !.6.0 !.7.0 !.8.0 !.rapid !.latest"
     display_tasks:
       - name: "test-ocsp-4.4"
@@ -154,7 +153,6 @@ buildvariants:
       - ".standalone .local !.5.0 !.6.0 !.7.0 !.8.0 !.rapid !.latest"
       - ".replicaset .local !.5.0 !.6.0 !.7.0 !.8.0 !.rapid !.latest"
       - ".sharded .local !.5.0 !.6.0 !.7.0 !.8.0 !.rapid !.latest"
-      - ".loadbalanced .local !.5.0 !.6.0 !.7.0 !.8.0 !.rapid !.latest"
       - ".ocsp !.5.0 !.6.0 !.7.0 !.8.0 !.rapid !.latest"
     display_tasks:
       - name: "test-ocsp-4.4"
@@ -234,7 +232,6 @@ buildvariants:
       - ".standalone .local !.5.0 !.6.0 !.7.0 !.8.0 !.rapid !.latest"
       - ".replicaset .local !.5.0 !.6.0 !.7.0 !.8.0 !.rapid !.latest"
       - ".sharded .local !.5.0 !.6.0 !.7.0 !.8.0 !.rapid !.latest"
-      - ".loadbalanced .local !.5.0 !.6.0 !.7.0 !.8.0 !.rapid !.latest"
       - ".ocsp !.5.0 !.6.0 !.7.0 !.8.0 !.rapid !.latest"
     display_tasks:
       - name: "test-ocsp-4.4"
@@ -314,7 +311,6 @@ buildvariants:
       - ".standalone .local !.5.0 !.6.0 !.7.0 !.8.0 !.rapid !.latest"
       - ".replicaset .local !.5.0 !.6.0 !.7.0 !.8.0 !.rapid !.latest"
       - ".sharded .local !.5.0 !.6.0 !.7.0 !.8.0 !.rapid !.latest"
-      - ".loadbalanced .local !.5.0 !.6.0 !.7.0 !.8.0 !.rapid !.latest"
       - ".ocsp !.5.0 !.6.0 !.7.0 !.8.0 !.rapid !.latest"
     display_tasks:
       - name: "test-ocsp-4.4"
diff --git a/.evergreen/config/templates/build/build-libmongoc.yml b/.evergreen/config/templates/build/build-libmongoc.yml
index 19c6963ea..4f268ce66 100644
--- a/.evergreen/config/templates/build/build-libmongoc.yml
+++ b/.evergreen/config/templates/build/build-libmongoc.yml
@@ -10,7 +10,7 @@
       - func: "compile driver"
         vars:
           PHP_VERSION: "%phpVersion%"
-          LIBMONGOC_VERSION: "1.28.0"
+          LIBMONGOC_VERSION: "1.28.1"
       - func: "upload build"
 
   - name: "build-php-%phpVersion%-libmongoc-next-stable"
@@ -22,11 +22,13 @@
           LIBMONGOC_VERSION: "r1.28"
       - func: "upload build"
 
-  - name: "build-php-%phpVersion%-libmongoc-latest"
-    tags: ["build-libmongoc", "php%phpVersion%"]
-    commands:
-      - func: "compile driver"
-        vars:
-          PHP_VERSION: "%phpVersion%"
-          LIBMONGOC_VERSION: "master"
-      - func: "upload build"
+# TODO: this currently fails as libmongoc master needs changes to build directories
+# We can re-enable this after switching to 1.29-dev
+#  - name: "build-php-%phpVersion%-libmongoc-latest"
+#    tags: ["build-libmongoc", "php%phpVersion%"]
+#    commands:
+#      - func: "compile driver"
+#        vars:
+#          PHP_VERSION: "%phpVersion%"
+#          LIBMONGOC_VERSION: "master"
+#      - func: "upload build"
diff --git a/.evergreen/config/templates/test-variant/libmongoc.yml b/.evergreen/config/templates/test-variant/libmongoc.yml
index 90099c6bf..e84365ca0 100644
--- a/.evergreen/config/templates/test-variant/libmongoc.yml
+++ b/.evergreen/config/templates/test-variant/libmongoc.yml
@@ -61,33 +61,33 @@
         execution_tasks:
           - ".ocsp .7.0"
 
-  - name: test-debian12-php-%phpVersion%-libmongoc-latest
-    tags: ["test", "libmongoc", "debian", "x64", "php%phpVersion%"]
-    display_name: "Test: Debian 12, PHP %phpVersion%, libmongoc latest"
-    run_on: debian12-small
-    expansions:
-      FETCH_BUILD_VARIANT: "build-debian12"
-      FETCH_BUILD_TASK: "build-php-%phpVersion%-libmongoc-latest"
-    depends_on:
-      - variant: "build-debian12"
-        name: "build-php-%phpVersion%-libmongoc-latest"
-    tasks:
-      - ".standalone .local !.4.0 !.4.2 !.4.4 !.5.0 !.6.0"
-      - ".replicaset .local !.4.0 !.4.2 !.4.4 !.5.0 !.6.0"
-      - ".sharded .local !.4.0 !.4.2 !.4.4 !.5.0 !.6.0"
-      - ".loadbalanced .local !.4.0 !.4.2 !.4.4 !.5.0 !.6.0"
-      - "test-atlas-connectivity"
-      - ".ocsp !.4.4 !.5.0 !.6.0"
-    display_tasks:
-      - name: "test-ocsp-latest"
-        execution_tasks:
-          - ".ocsp .latest"
-      - name: "test-ocsp-rapid"
-        execution_tasks:
-          - ".ocsp .rapid"
-      - name: "test-ocsp-8.0"
-        execution_tasks:
-          - ".ocsp .8.0"
-      - name: "test-ocsp-7.0"
-        execution_tasks:
-          - ".ocsp .7.0"
+#  - name: test-debian12-php-%phpVersion%-libmongoc-latest
+#    tags: ["test", "libmongoc", "debian", "x64", "php%phpVersion%"]
+#    display_name: "Test: Debian 12, PHP %phpVersion%, libmongoc latest"
+#    run_on: debian12-small
+#    expansions:
+#      FETCH_BUILD_VARIANT: "build-debian12"
+#      FETCH_BUILD_TASK: "build-php-%phpVersion%-libmongoc-latest"
+#    depends_on:
+#      - variant: "build-debian12"
+#        name: "build-php-%phpVersion%-libmongoc-latest"
+#    tasks:
+#      - ".standalone .local !.4.0 !.4.2 !.4.4 !.5.0 !.6.0"
+#      - ".replicaset .local !.4.0 !.4.2 !.4.4 !.5.0 !.6.0"
+#      - ".sharded .local !.4.0 !.4.2 !.4.4 !.5.0 !.6.0"
+#      - ".loadbalanced .local !.4.0 !.4.2 !.4.4 !.5.0 !.6.0"
+#      - "test-atlas-connectivity"
+#      - ".ocsp !.4.4 !.5.0 !.6.0"
+#    display_tasks:
+#      - name: "test-ocsp-latest"
+#        execution_tasks:
+#          - ".ocsp .latest"
+#      - name: "test-ocsp-rapid"
+#        execution_tasks:
+#          - ".ocsp .rapid"
+#      - name: "test-ocsp-8.0"
+#        execution_tasks:
+#          - ".ocsp .8.0"
+#      - name: "test-ocsp-7.0"
+#        execution_tasks:
+#          - ".ocsp .7.0"
diff --git a/.evergreen/config/templates/test-variant/php-full.yml b/.evergreen/config/templates/test-variant/php-full.yml
index cba0d8412..e12cd97dc 100644
--- a/.evergreen/config/templates/test-variant/php-full.yml
+++ b/.evergreen/config/templates/test-variant/php-full.yml
@@ -72,7 +72,6 @@
       - ".standalone .local !.5.0 !.6.0 !.7.0 !.8.0 !.rapid !.latest"
       - ".replicaset .local !.5.0 !.6.0 !.7.0 !.8.0 !.rapid !.latest"
       - ".sharded .local !.5.0 !.6.0 !.7.0 !.8.0 !.rapid !.latest"
-      - ".loadbalanced .local !.5.0 !.6.0 !.7.0 !.8.0 !.rapid !.latest"
       - ".ocsp !.5.0 !.6.0 !.7.0 !.8.0 !.rapid !.latest"
     display_tasks:
       - name: "test-ocsp-4.4"
diff --git a/.github/actions/windows/prepare-build/action.yml b/.github/actions/windows/prepare-build/action.yml
index b48b89e08..ab674a409 100644
--- a/.github/actions/windows/prepare-build/action.yml
+++ b/.github/actions/windows/prepare-build/action.yml
@@ -19,12 +19,13 @@ runs:
   steps:
     - name: Setup PHP SDK
       id: setup-php
-      uses: php/setup-php-sdk@v0.9
+      uses: php/setup-php-sdk@v0.10
       with:
         version: ${{ inputs.version }}
         arch: ${{ inputs.arch }}
         ts: ${{ inputs.ts }}
         deps: openssl
+        cache: true
 
     - name: Enable Developer Command Prompt
       uses: ilammy/msvc-dev-cmd@v1
diff --git a/config.m4 b/config.m4
index 6c9d5a238..4041edc09 100644
--- a/config.m4
+++ b/config.m4
@@ -276,7 +276,7 @@ if test "$PHP_MONGODB" != "no"; then
   PHP_MONGODB_MONGOCRYPT_VERSION_STRING="None"
 
   if test "$PHP_MONGODB_SYSTEM_LIBS" != "no"; then
-    PKG_CHECK_MODULES([PHP_MONGODB_BSON], [libbson-1.0 >= 1.28.0], [
+    PKG_CHECK_MODULES([PHP_MONGODB_BSON], [libbson-1.0 >= 1.28.1], [
       PHP_MONGODB_BSON_VERSION=`$PKG_CONFIG libbson-1.0 --modversion`
       PHP_MONGODB_BSON_VERSION_STRING="System ($PHP_MONGODB_BSON_VERSION)"
 
@@ -284,10 +284,10 @@ if test "$PHP_MONGODB" != "no"; then
       PHP_EVAL_LIBLINE($PHP_MONGODB_BSON_LIBS, MONGODB_SHARED_LIBADD)
       AC_DEFINE(HAVE_SYSTEM_LIBBSON, 1, [Use system libbson])
     ],[
-      AC_MSG_ERROR([Could not find system library for libbson >= 1.28.0])
+      AC_MSG_ERROR([Could not find system library for libbson >= 1.28.1])
     ])
 
-    PKG_CHECK_MODULES([PHP_MONGODB_MONGOC], [libmongoc-1.0 >= 1.28.0], [
+    PKG_CHECK_MODULES([PHP_MONGODB_MONGOC], [libmongoc-1.0 >= 1.28.1], [
       PHP_MONGODB_BSON_VERSION=`$PKG_CONFIG libbson-1.0 --modversion`
       PHP_MONGODB_BSON_VERSION_STRING="System ($PHP_MONGODB_BSON_VERSION)"
 
@@ -295,7 +295,7 @@ if test "$PHP_MONGODB" != "no"; then
       PHP_EVAL_LIBLINE($PHP_MONGODB_MONGOC_LIBS, MONGODB_SHARED_LIBADD)
       AC_DEFINE(HAVE_SYSTEM_LIBMONGOC, 1, [Use system libmongoc])
     ],[
-      AC_MSG_ERROR(Could not find system library for libmongoc >= 1.28.0)
+      AC_MSG_ERROR(Could not find system library for libmongoc >= 1.28.1)
     ])
 
     if test "$PHP_MONGODB_CLIENT_SIDE_ENCRYPTION" != "no"; then
diff --git a/sbom.json b/sbom.json
index 7319749c7..11c0e862b 100644
--- a/sbom.json
+++ b/sbom.json
@@ -19,22 +19,22 @@
       "version": "1.11.0"
     },
     {
-      "bom-ref": "pkg:github/mongodb/mongo-c-driver@1.28.0",
+      "bom-ref": "pkg:github/mongodb/mongo-c-driver@1.28.1",
       "externalReferences": [
         {
           "type": "distribution",
-          "url": "https://github.com/mongodb/mongo-c-driver/archive/refs/tags/1.28.0.tar.gz"
+          "url": "https://github.com/mongodb/mongo-c-driver/archive/refs/tags/1.28.1.tar.gz"
         },
         {
           "type": "website",
-          "url": "https://github.com/mongodb/mongo-c-driver/tree/1.28.0"
+          "url": "https://github.com/mongodb/mongo-c-driver/tree/1.28.1"
         }
       ],
       "group": "mongodb",
       "name": "mongo-c-driver",
-      "purl": "pkg:github/mongodb/mongo-c-driver@1.28.0",
+      "purl": "pkg:github/mongodb/mongo-c-driver@1.28.1",
       "type": "library",
-      "version": "1.28.0"
+      "version": "1.28.1"
     }
   ],
   "dependencies": [
@@ -42,11 +42,11 @@
       "ref": "pkg:github/mongodb/libmongocrypt@1.11.0"
     },
     {
-      "ref": "pkg:github/mongodb/mongo-c-driver@1.28.0"
+      "ref": "pkg:github/mongodb/mongo-c-driver@1.28.1"
     }
   ],
   "metadata": {
-    "timestamp": "2024-09-20T07:58:30.627473+00:00",
+    "timestamp": "2024-10-16T08:27:04.343416+00:00",
     "tools": [
       {
         "externalReferences": [
@@ -90,7 +90,7 @@
     ]
   },
   "serialNumber": "urn:uuid:acb30d08-ee47-4ff0-b301-d66ef1f54082",
-  "version": 4,
+  "version": 5,
   "$schema": "http://cyclonedx.org/schema/bom-1.5.schema.json",
   "bomFormat": "CycloneDX",
   "specVersion": "1.5"
diff --git a/src/LIBMONGOC_VERSION_CURRENT b/src/LIBMONGOC_VERSION_CURRENT
index cfc730712..450a687b2 100644
--- a/src/LIBMONGOC_VERSION_CURRENT
+++ b/src/LIBMONGOC_VERSION_CURRENT
@@ -1 +1 @@
-1.28.0
+1.28.1
diff --git a/src/libmongoc b/src/libmongoc
index a463a46c3..97f166d8d 160000
--- a/src/libmongoc
+++ b/src/libmongoc
@@ -1 +1 @@
-Subproject commit a463a46c38cb6b552f2da4b3ae63e393dfe0a9a6
+Subproject commit 97f166d8d784d6096d48ba288f98b48028cdfe8b