diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 0acacec..7e096dd 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -219,10 +219,10 @@ jobs:
     runs-on: ubuntu-24.04
     timeout-minutes: 120
     env:
-      # openkal 0.18.0, which this release is written against, is the one
-      # openkal-platform 0.19.0's version group names; the released mcpp's
+      # openkal 0.19.0, which this release is written against, is the one
+      # openkal-platform 0.20.0's version group names; the released mcpp's
       # openkal rows pin 0.18.0, whose group names openkal 0.17.1.
-      MCPP_PLATFORM: openkal-platform@0.19.0
+      MCPP_PLATFORM: openkal-platform@0.20.0
     defaults:
       run:
         shell: bash
@@ -269,10 +269,10 @@ jobs:
     runs-on: ${{ matrix.os }}
     timeout-minutes: 45
     env:
-      # openkal 0.18.0, which this release is written against, is the one
-      # openkal-platform 0.19.0's version group names; the released mcpp's
+      # openkal 0.19.0, which this release is written against, is the one
+      # openkal-platform 0.20.0's version group names; the released mcpp's
       # openkal rows pin 0.18.0, whose group names openkal 0.17.1.
-      MCPP_PLATFORM: openkal-platform@0.19.0
+      MCPP_PLATFORM: openkal-platform@0.20.0
     strategy:
       fail-fast: false
       matrix:
diff --git a/CHANGELOG.md b/CHANGELOG.md
index a764b18..777064e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,17 @@
 # Changelog
 
+## 0.2.5
+
+- **openkal 0.19.** The implementations of openkal 0.19 (openkal-linux 0.20.0,
+  openkal-macos 0.17.0, openkal-windows 0.15.0, openkal-emscripten 0.8.0), which
+  state the physical cores and set a context's claim on the processors
+  (`kal_task_cores`, `kal_task_set_priority`). This library's own interface is
+  unchanged: no program above it needs either yet, and os grows by its
+  consumers.
+- **An ok image over this release selects openkal-platform 0.20.0** or a later
+  group naming openkal 0.19; `checks/hosted` and the image checks take theirs
+  from 0.20.0.
+
 ## 0.2.4
 
 - **openkal 0.18.** The implementations of openkal 0.18 (openkal-linux 0.19.0,
diff --git a/README.md b/README.md
index 5a6ca1c..346cb66 100644
--- a/README.md
+++ b/README.md
@@ -6,7 +6,7 @@ with compile-time platform constants and a few platform modules.
 
 ```toml
 [dependencies]
-os = { namespace = "mcpplibs", version = "0.2.4" }
+os = { namespace = "mcpplibs", version = "0.2.5" }
 ```
 
 ```cpp
diff --git a/checks/hosted/mcpp.toml b/checks/hosted/mcpp.toml
index 4f3d502..2453120 100644
--- a/checks/hosted/mcpp.toml
+++ b/checks/hosted/mcpp.toml
@@ -13,7 +13,7 @@ version = "0.1.0"
 os = { path = "../.." }
 
 [target.'cfg(any(linux, macos, windows))']
-platform = "openkal-platform@0.19.0"
+platform = "openkal-platform@0.20.0"
 
 # The tests are the package's own, each reached by an include from
 # tests/<name>.cpp here (a test program is a file of the package that runs it).
diff --git a/mcpp.toml b/mcpp.toml
index ce46ede..e8ded15 100644
--- a/mcpp.toml
+++ b/mcpp.toml
@@ -1,7 +1,7 @@
 [package]
 namespace   = "mcpplibs"
 name        = "os"
-version     = "0.2.4"
+version     = "0.2.5"
 description = "mcpplibs.os: a C++ operating-system library over openkal --- processes, files, environment, terminals, directories and local IPC, with compile-time platform constants and a few platform modules."
 license     = "Apache-2.0"
 authors     = ["mcpplibs"]
@@ -12,23 +12,23 @@ repo        = "https://github.com/mcpplibs/os"
 # own C and C++ runtime. A program that wants the standalone arrangement, or
 # the image arrangement of `<arch>-openkal`, selects it in its own manifest.
 [dependencies]
-openkal = "0.18.0"
+openkal = "0.19.0"
 
 [target.linux.dependencies]
-openkal-linux = "0.19.0"
+openkal-linux = "0.20.0"
 
 [target.macos.dependencies]
-openkal-macos = "0.16.0"
+openkal-macos = "0.17.0"
 
 [target.windows.dependencies]
-openkal-windows = "0.14.0"
+openkal-windows = "0.15.0"
 
 # Emscripten (`wasm32-emscripten`): openkal written above the C library, with
 # twelve of openkal's fifteen interfaces. `openkal.process', `openkal.exec' and
 # `openkal.space' are absent, so a program that starts one fails at link
 # naming the symbol; `openkal.task' is present in a `-pthread' link only.
 [target.'cfg(os = "emscripten")'.dependencies]
-openkal-emscripten = "0.7.0"
+openkal-emscripten = "0.8.0"
 
 [targets.os]
 kind = "lib"