diff --git a/.github/workflows/checks.yml b/.github/workflows/checks.yml
index 06926f375..dc11d46a8 100644
--- a/.github/workflows/checks.yml
+++ b/.github/workflows/checks.yml
@@ -49,7 +49,8 @@ jobs:
       - name: Setup mdBook
         uses: peaceiris/actions-mdbook@v1
         with:
-          mdbook-version: 'latest'
+          # if this changes, change it in cli/Cargo.toml and .github/workflows/publish-docs.yml as well
+          mdbook-version: '0.4.10'
 
       - name: Cache cargo registry
         uses: actions/cache@v1
diff --git a/.github/workflows/publish-docs.yml b/.github/workflows/publish-docs.yml
index e0e979004..8bb43f89c 100644
--- a/.github/workflows/publish-docs.yml
+++ b/.github/workflows/publish-docs.yml
@@ -15,7 +15,8 @@ jobs:
       - name: Setup mdBook
         uses: peaceiris/actions-mdbook@v1
         with:
-          mdbook-version: 'latest'
+          # if this changes, change it in cli/Cargo.toml and .github/workflows/publish-docs.yml as well
+          mdbook-version: '0.4.10'
 
       - name: Cache cargo registry
         uses: actions/cache@v1
diff --git a/Cargo.lock b/Cargo.lock
index b49d44ee6..c28fa2e1e 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1215,9 +1215,9 @@ dependencies = [
 
 [[package]]
 name = "handlebars"
-version = "3.5.5"
+version = "4.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4498fc115fa7d34de968184e473529abb40eeb6be8bc5f7faba3d08c316cb3e3"
+checksum = "28f0fe89affef47e2c9729030a8f6e79df34cb66b8a44ecf91dad43f31150559"
 dependencies = [
  "log",
  "pest",
@@ -1701,9 +1701,9 @@ checksum = "7ffc5c5338469d4d3ea17d269fa8ea3512ad247247c30bd2df69e68309ed0a08"
 
 [[package]]
 name = "mdbook"
-version = "0.4.9"
+version = "0.4.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "aeb86d199d0c1e8d41f3a9e9b0ba8639d6951a10043129159809ac9c18e3ce05"
+checksum = "b6da0e609de0d4a7e0d42367d91b87117e3dce74d3d1699efeda1fefb2a6fa85"
 dependencies = [
  "ammonia",
  "anyhow",
diff --git a/cli/Cargo.toml b/cli/Cargo.toml
index 7f3884ae5..bcc34aeda 100644
--- a/cli/Cargo.toml
+++ b/cli/Cargo.toml
@@ -27,7 +27,8 @@ lazy_static = "1"
 iso8601-duration = "0.1"
 
 # only needed for usage-docs
-mdbook = { version = "0.4.9", optional = true }
+# if the mdbook version changes, change it in .github/workflows/publish-docs.yml and .github/workflows/checks.yml as well
+mdbook = { version = "0.4.10", optional = true }
 serde_json = { version = "*", optional = true }
 
 [dependencies.taskchampion]