diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index a1b56b05..922ab123 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -16,14 +16,19 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        java: [ '8', '11', '16', '17', '19']
-        runs-on: [ubuntu-latest, macos-latest, windows-2019 ]
+        java: [ '8', '11', '16', '17', '19', '21' ]
+        runs-on: [ubuntu-latest, macos-12, windows-2019] # Note macos-12, not latest/14, due to hdf5 install issue
+        exclude:
+          - runs-on: macos-latest
+            java: "8"
+          - runs-on: macos-latest
+            java: "16"
 
     name: Test on Java ${{ matrix.Java }} on ${{ matrix.runs-on }}
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Set up JDK ${{ matrix.Java }}
-      uses: actions/setup-java@v3
+      uses: actions/setup-java@v4
       with:
         java-version: ${{ matrix.Java }}
         distribution: 'temurin'
diff --git a/.github/workflows/docs.yml b/.github/workflows/docs.yml
index 2d1c5f0d..380031c4 100644
--- a/.github/workflows/docs.yml
+++ b/.github/workflows/docs.yml
@@ -13,18 +13,18 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - uses: nelonoel/branch-name@v1.0.1
 
     - name: Set up JDK 11
-      uses: actions/setup-java@v3
+      uses: actions/setup-java@v4
       with:
         java-version: 11
         distribution: 'temurin'
         java-package: jdk
 
     - name: Set up Python 3.9
-      uses: actions/setup-python@v4
+      uses: actions/setup-python@v5
       with:
         python-version: 3.9
 
@@ -34,14 +34,14 @@ jobs:
         pip install ghp-import
 
     - name: Checkout NeuroML2
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
       with:
         repository: NeuroML/NeuroML2
         ref: development
         path: NeuroML2
 
     - name: Checkout org.lemsml
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
       with:
         repository: LEMS/jLEMS
         ref: development
@@ -49,14 +49,14 @@ jobs:
 
 
     - name: Checkout org.neuroml.model.injectingplugin
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
       with:
         repository: NeuroML/org.neuroml.model.injectingplugin
         ref: development
         path: org.neuroml.model.injectingplugin
 
     - name: Checkout org.neuroml.model
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
       with:
         repository: NeuroML/org.neuroml.model
         ref: development
diff --git a/pom.xml b/pom.xml
index c38acde7..8df75dd3 100644
--- a/pom.xml
+++ b/pom.xml
@@ -91,8 +91,8 @@
                 <artifactId>maven-compiler-plugin</artifactId>
                 <version>3.0</version>
                 <configuration>
-                    <source>1.7</source>
-                    <target>1.7</target>
+                    <source>1.8</source>
+                    <target>1.8</target>
                 </configuration>
             </plugin>
             <plugin>