diff --git a/.env b/.env
index 56d5244..aba142f 100644
--- a/.env
+++ b/.env
@@ -1,6 +1,6 @@
-MDBOOK_VERSION=0.4.6
-MDBOOK_LINKCHECK_VERSION=0.7.2
-MDBOOK_TOC_VERSION=0.6.1
+MDBOOK_VERSION=0.4.8
+MDBOOK_LINKCHECK_VERSION=0.7.4
+MDBOOK_TOC_VERSION=0.6.3
 
 GIT_DEPLOY_DIR=book/html
 GIT_DEPLOY_BRANCH=gh-pages