diff --git a/.github/workflows/action-ci.yml b/.github/workflows/action-ci.yml
index d55b18e..db8689b 100644
--- a/.github/workflows/action-ci.yml
+++ b/.github/workflows/action-ci.yml
@@ -6,7 +6,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest] # macos-latest
-        ruby: ['truffleruby', 'jruby', '2.7', '3.0', '3.1', '3.2', '3.3'] # Due to https://github.com/actions/runner/issues/849, we have to use quotes
+        ruby: ['2.7', '3.0', '3.1', '3.2', '3.3'] # add 'truffleruby', 'jruby', for releases - and remember to use quotes due to https://github.com/actions/runner/issues/849
 
     runs-on: ${{ matrix.os }}
 
diff --git a/README.markdown b/README.markdown
index fc58d78..e485226 100644
--- a/README.markdown
+++ b/README.markdown
@@ -17,16 +17,17 @@ The only other runtime dependency is Ruby's latest code loader [**zeitwerk**](ht
 
 ### Ruby version
 
-| Chimera version | Ruby version                        |
-|:----------------|:------------------------------------|
-| >= 1.6          | >= 2.7 (all 3.x versions supported) |
-| >= 1.4          | >= 2.5 (3.0 compatibility ensured)  |
-| >= 1.1          | >= 2.5                              |
-| =  1.0          | >= 2.4, <= 3.0                      |
-| <= 0.5          | >= 2.1, <= 3.0                      |
-
-The test suite of v1.4 passes on **MRI Ruby** (2.5, 2.6, 2.7, 3.0) and on **JRuby**, but not on **TruffleRuby**.
-The test suite of v1.6 passes on **MRI Ruby** (2.7, 3.0, 3.1, 3.2, 3.3) and on **JRuby** and **TruffleRuby**.
+| Chimera version | MRI Ruby version                    | JRuby | TruffleRuby |
+|:----------------|:------------------------------------|:-----:|:-----------:|
+| >= 1.6          | >= 2.7 (all 3.x versions supported) |  yes  |     yes     |
+| >= 1.4          | >= 2.5 (3.0 compatibility ensured)  |  yes  |     no      |
+| >= 1.1          | >= 2.5                              |   ?   |      ?      |
+| =  1.0          | >= 2.4, <= 3.0                      |   ?   |      ?      |
+| <= 0.5          | >= 2.1, <= 3.0                      |   ?   |      ?      |
+
+The test suite of v1.4 passes on **MRI Ruby** (2.5, 2.6, 2.7, 3.0) and on **JRuby**, but not on **TruffleRuby**.  
+The test suite of v1.6 passes on **MRI Ruby** (2.7, 3.0, 3.1, 3.2, 3.3) and on **JRuby** and **TruffleRuby**.  
+The non-MRI Rubys are not part of the regular Matrix, as their CI jobs take 3x as long, but included for new releases.
 
 ### ENV variables