diff --git a/.github/workflows/openkal-compat.yml b/.github/workflows/openkal-compat.yml
index 6caf5088..e0418807 100644
--- a/.github/workflows/openkal-compat.yml
+++ b/.github/workflows/openkal-compat.yml
@@ -42,7 +42,7 @@ env:
   # run if this drifts from pins.toml. See the comment beside `mcpp` in
   # pins.toml for why this pin, not just validate.yml's, is gated by the
   # index floor.
-  MCPP_VERSION: "2026.11.14.1"
+  MCPP_VERSION: "2026.11.15.1"
   # CROSS-VALIDATION BEFORE A RELEASE, NOT AFTER IT.
   #
   # Empty in an ordinary run, so this measurement keeps using the RELEASED
diff --git a/.github/workflows/validate.yml b/.github/workflows/validate.yml
index 9ad67391..8cb247cc 100644
--- a/.github/workflows/validate.yml
+++ b/.github/workflows/validate.yml
@@ -451,9 +451,10 @@ env:
   # 2026.11.7.2: the built-in platform as one release, and the floor
   # mcpplibs.mtest 0.1.0 states.
   #
-  # 2026.11.14.1: the newest release; the index validates with the engine its
-  # consumers install (openkal-run 0.6.3 states 2026.11.13.1).
-  MCPP_VERSION: "2026.11.14.1"
+  # 2026.11.15.1: the newest release; the index validates with the engine its
+  # consumers install (openkal-platform 0.28.0 states 2026.11.14.1, and the
+  # engine's built-in platform is 0.28.0).
+  MCPP_VERSION: "2026.11.15.1"
 
 jobs:
   lint:
diff --git a/.github/workflows/xpkgindex-update.yml b/.github/workflows/xpkgindex-update.yml
index 5688e4e6..c2216583 100644
--- a/.github/workflows/xpkgindex-update.yml
+++ b/.github/workflows/xpkgindex-update.yml
@@ -25,7 +25,7 @@ concurrency:
 
 env:
   PYTHONUTF8: '1'
-  MCPP_VERSION: '2026.11.14.1'
+  MCPP_VERSION: '2026.11.15.1'
   # CROSS-VALIDATION BEFORE A RELEASE: a candidate that needs an mcpp newer
   # than the pin (its package states the floor) is built with mcpp built from
   # this branch of mcpp-community/mcpp, as openkal-compat.yml measures with it.
diff --git a/tests/openkal/pins.toml b/tests/openkal/pins.toml
index 1def820d..b3e359c4 100644
--- a/tests/openkal/pins.toml
+++ b/tests/openkal/pins.toml
@@ -18,6 +18,8 @@ toolchain = "llvm@22.1.8"
 # index requires mcpp >= 2026.9.18.1 but this is mcpp 2026.9.17.3 [E0006]"
 # before a single line of the member's own source is read.
 #
+# 2026-11-15: measurement engine 2026.11.15.1 (its built-in platform is
+# openkal-platform 0.28.0) matches all CI workflows.
 # 2026-11-10: measurement engine 2026.11.10.1 (openkal-image 0.6.0 states mcpp >=
 # 2026.11.10.1) matches all CI workflows.
 # 2026-11-09: measurement engine 2026.11.9.1 (targets and providers; openkal-platform
@@ -155,7 +157,7 @@ toolchain = "llvm@22.1.8"
 # openkal-musl 0.16.0 and openkal-llvm-runtime 0.12.0), because a pin that
 # moves onto an unreachable or divergent asset fails every member at once and
 # reports it as a compatibility result.
-mcpp      = "2026.11.14.1"
+mcpp      = "2026.11.15.1"
 
 # The Windows target is named for the C environment the graph presents there,
 # which is musl's (openkal-musl declares `[c-abi] presents = "posix"`), not