diff --git a/CHANGES.md b/CHANGES.md
index 2e2d95e47..3c004a4c6 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,5 +1,39 @@
 # Revision History for Microkit
 
+## Release 2.3.1
+
+This release contains a security fix, various bug fixes, and new board support.
+
+### Security
+
+* Endpoint and Notification capabilities now only get the rights they need.
+  Previously the tool gave all rights, which let a let a PD do more than
+  intended. For example, a client PD with a PPC to a server PD can receive
+  on the server's Endpoint and consume all the messages meant for the server.
+
+### Bug fixes
+
+* When using the domain scheduler, a VM's VCPUs are now placed in the same
+  domain as the VMM PD. Previously VM performance was badly degraded.
+* The tool now checks that VM priority in the SDF are valid.
+* The second CPU cluster on the RockPro64 is now enabled in SMP
+  configurations.
+* The tool now reports an error for duplicate MSI or I/O APIC interrupt
+  sources. The kernel does not detect this, so it previously went
+  unnoticed.
+
+### Board support
+
+* Raspberry Pi 5B
+
+### Known issue
+
+* Currently, on x86-64, VMs will not work if you create more than 1 VM per
+  system or use the SMP configuration of `x86_64_generic_vtx`. This is due
+  to a bug in seL4, which was fixed in
+  [PR 1732](https://github.com/seL4/seL4/pull/1732). The fix will be brought
+  to Microkit on the next seL4 and Microkit release.
+
 ## Release 2.3.0
 
 This release contains quite a few new features:
diff --git a/Cargo.lock b/Cargo.lock
index 67bd2d7ad..267400cb3 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -135,7 +135,7 @@ checksum = "ed5909b6e89a2db4456e54cd5f673791d7eca6732202bbf2a9cc504fe2f9b84a"
 
 [[package]]
 name = "initialiser"
-version = "2.3.0-dev"
+version = "2.3.1"
 dependencies = [
  "sel4-capdl-initializer",
 ]
@@ -194,7 +194,7 @@ checksum = "88904434abc2901f197fe8cc55f0445e7ded921dba5911dad2e2b39b48e663c4"
 
 [[package]]
 name = "microkit-tool"
-version = "2.3.0-dev"
+version = "2.3.1"
 dependencies = [
  "rkyv",
  "roxmltree",
diff --git a/VERSION b/VERSION
index d64a64435..2bf1c1ccf 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-2.3.0-dev
+2.3.1
diff --git a/docs/manual.md b/docs/manual.md
index 5fdf44f61..a77392be4 100644
--- a/docs/manual.md
+++ b/docs/manual.md
@@ -4,7 +4,7 @@
 -->
 
 ---
-title: Microkit User Manual (v2.3.0-dev)
+title: Microkit User Manual (v2.3.1)
 documentclass: article
 classoption:
 - english
diff --git a/initialiser/Cargo.toml b/initialiser/Cargo.toml
index 7dbc58cc3..9b2f3894e 100644
--- a/initialiser/Cargo.toml
+++ b/initialiser/Cargo.toml
@@ -6,7 +6,7 @@
 
 [package]
 name = "initialiser"
-version = "2.3.0-dev"
+version = "2.3.1"
 edition = "2021"
 rust-version = "1.88.0"
 
diff --git a/platforms.yml b/platforms.yml
index 067caf2d7..1e4b81293 100644
--- a/platforms.yml
+++ b/platforms.yml
@@ -16,7 +16,7 @@
 platforms:
   - name: rpi5b_2gb
     cmake_plat: bcm2712
-    since: dev
+    since: 2.3.1
   - name: stm32mp2
     cmake_plat: stm32mp2
     since: 2.3.0
diff --git a/tool/microkit/Cargo.toml b/tool/microkit/Cargo.toml
index 27e2fc0c9..b8611dc27 100644
--- a/tool/microkit/Cargo.toml
+++ b/tool/microkit/Cargo.toml
@@ -6,7 +6,7 @@
 
 [package]
 name = "microkit-tool"
-version = "2.3.0-dev"
+version = "2.3.1"
 edition = "2021"
 rust-version = "1.94.0"