diff --git a/.github/workflows/sdk.yaml b/.github/workflows/sdk.yaml
index 30610d008..79083bea1 100644
--- a/.github/workflows/sdk.yaml
+++ b/.github/workflows/sdk.yaml
@@ -19,7 +19,7 @@ on:
       - '*.*.*'
 
 env:
-  SEL4_VERSION: 15.0.0
+  SEL4_VERSION: e912dff7341cf3b35475c3a7eee9a90c61b367a8
 
 # To reduce the load we cancel any older runs of this workflow for the current
 # PR. For deployment to the main branch, the workflow will run on each push,
diff --git a/DEVELOPER.md b/DEVELOPER.md
index 5a2284418..ccff266e3 100644
--- a/DEVELOPER.md
+++ b/DEVELOPER.md
@@ -120,7 +120,7 @@ It should be noted that while Microkit uses mainline seL4, it is fairly tied to
 specific version used.
 
 For this version of Microkit please use the following tag:
-`15.0.0`.
+`e912dff7341cf3b35475c3a7eee9a90c61b367a8`.
 
 ## Building the SDK