diff --git a/ports/immer/portfile.cmake b/ports/immer/portfile.cmake
index 4c3a1e6be6..c737b80573 100644
--- a/ports/immer/portfile.cmake
+++ b/ports/immer/portfile.cmake
@@ -4,7 +4,7 @@ vcpkg_from_github(
     OUT_SOURCE_PATH SOURCE_PATH
     REPO arximboldi/immer
     REF "v${VERSION}"
-    SHA512 077778c9f5116031dfabb22343339193689c01fb45680f5f0c713ba712abe0c6fc77560a7e0e69d08b5064a2a716a900e0e04053c280fe03fd808d2358cf8738
+    SHA512 b001a23b503610ce989f68fee8136723b3b2cc788558a37a373aaa0347acf615a647b44759cda7f5ab4a6f9f15f46dcb9f22eac569310201d95161e8892e3619
     HEAD_REF master
 )
 
diff --git a/ports/immer/vcpkg.json b/ports/immer/vcpkg.json
index 903bff6ec8..f9e477515e 100644
--- a/ports/immer/vcpkg.json
+++ b/ports/immer/vcpkg.json
@@ -1,6 +1,6 @@
 {
   "name": "immer",
-  "version": "0.9.0",
+  "version": "0.9.1",
   "description": "Postmodern immutable and persistent data structures for C++",
   "homepage": "https://sinusoid.es/immer/",
   "license": "BSL-1.0",
diff --git a/versions/baseline.json b/versions/baseline.json
index 8c28c7748e..66c6c857e3 100644
--- a/versions/baseline.json
+++ b/versions/baseline.json
@@ -3933,7 +3933,7 @@
       "port-version": 1
     },
     "immer": {
-      "baseline": "0.9.0",
+      "baseline": "0.9.1",
       "port-version": 0
     },
     "implot": {
diff --git a/versions/i-/immer.json b/versions/i-/immer.json
index ec2e94ca05..9a4cb17e2a 100644
--- a/versions/i-/immer.json
+++ b/versions/i-/immer.json
@@ -1,5 +1,10 @@
 {
   "versions": [
+    {
+      "git-tree": "f13329bd1ed9ef08eafe8120e3f4ecc8aeb2afff",
+      "version": "0.9.1",
+      "port-version": 0
+    },
     {
       "git-tree": "fe4bb890b8f12cb1b9c7471feb02f7fd5c22a5fd",
       "version": "0.9.0",