diff --git a/.github/workflows/php.yml b/.github/workflows/php.yml
index 53597a1..9e9671c 100644
--- a/.github/workflows/php.yml
+++ b/.github/workflows/php.yml
@@ -16,17 +16,17 @@ jobs:
 
     strategy:
       matrix:
-        php-versions: ['8.1']
+        versions: [{php: '8.1', solr: '9.4.0'}]
 
-    name: PHP ${{ matrix.php-versions }} Test
+    name: PHP ${{ matrix.versions.php }} Test
 
     steps:
       - uses: actions/checkout@v3
 
-      - name: Setup PHP ${{ matrix.php-versions }}
+      - name: Setup PHP ${{ matrix.versions.php }}
         uses: shivammathur/setup-php@v2
         with:
-          php-version: ${{ matrix.php-versions }}
+          php-version: ${{ matrix.versions.php }}
 
       - name: Check PHP Version
         run: php -v
@@ -34,22 +34,29 @@ jobs:
       - name: Install Composer and Dependencies
         run: sudo apt-get update && curl -s http://getcomposer.org/installer | php && php composer.phar self-update && php composer.phar install
 
-      - name: Solr
-        run: sudo bash bin/install_solr_docker.sh
+      - name: Get Solr ${{ matrix.versions.solr }} from Cache
+        id: cache-solr
+        uses: actions/cache@v3
+        with:
+          path: downloads
+          key: solr-${{ matrix.versions.solr }}
+
+      - name: Install Solr ${{ matrix.versions.solr }}
+        run: sudo bash bin/install_solr_docker.sh --version ${{ matrix.versions.solr }}
 
       - name: Start MySQL
         run: sudo systemctl start mysql.service
 
-      - name: Prepare workspace
+      - name: Prepare Workspace
         run: ant prepare-workspace
 
-      - name: Prepare search config
+      - name: Prepare Search Config
         run: ant prepare-config
 
-      - name: Prepare database
+      - name: Prepare Database
         run: bash vendor/bin/opus4db --adminpwd root --userpwd root --sqlpwd root
 
-      - name: Basic PHP file check
+      - name: Basic PHP File Check
         run: ant lint
 
       - name: Tests
diff --git a/bin/install_solr_docker.sh b/bin/install_solr_docker.sh
old mode 100644
new mode 100755
index c36ac9a..b66a8b7
--- a/bin/install_solr_docker.sh
+++ b/bin/install_solr_docker.sh
@@ -1,8 +1,60 @@
 #!/usr/bin/env bash
 
-SOLR_VERSION="9.4.0"
-wget -q "https://www.apache.org/dyn/closer.lua/solr/solr/$SOLR_VERSION/solr-$SOLR_VERSION.tgz?action=download" -O - | tar -xz
-cd solr-$SOLR_VERSION
+#
+# Script to install Solr. By default, version 9.4.0 will be installed.
+# Another Solr version can be specified using the `--version` option.
+
+# Define variables and their default values
+version="9.4.0"
+
+# Parse command line options
+while [ $# -gt 0 ]; do
+    if [[ $1 == "--"* ]]; then # only deal with long options
+        if [[ -n "$2" && $2 != "-"* ]]; then # ignore options without a value
+            # Create variable name from option name
+            v="${1/--/}" # uses parameter expansion removing '--'
+
+            # Read option value into variable
+            declare "$v"="$2"
+
+            # Process next option
+            shift
+        fi
+    fi
+    shift
+done
+
+# Check --version input
+if ! [[ "$version" =~ ^[0-9]+\.[0-9]+\.[0-9]+$ ]]; then
+  echo "Unrecognized version number: $version"
+  echo "The --version option requires a 3-digit version number, e.g.: 9.4.0"
+  exit 1
+fi
+
+SOLR_VERSION="$version"
+SOLR_TAR="solr-$SOLR_VERSION.tgz"
+
+mkdir -p "downloads"
+cd downloads
+
+# Download Solr version
+if test ! -f "$SOLR_TAR"; then
+  # the Solr download URL differs for versions >=9.0.0
+  if [[ "$version" =~ ^[1-8]\.[0-9]+\.[0-9]+$ ]]; then
+    SOLR_URL="https://archive.apache.org/dist/lucene/solr/$SOLR_VERSION/$SOLR_TAR"
+  elif [[ "$version" =~ ^(9|[1-9][0-9]+)\.[0-9]+\.[0-9]+$ ]]; then
+    SOLR_URL="https://www.apache.org/dyn/closer.lua/solr/solr/$SOLR_VERSION/$SOLR_TAR?action=download"
+  fi
+
+  echo "Getting: $SOLR_URL"
+  wget -q --show-progress --progress=bar:force $SOLR_URL -O $SOLR_TAR
+fi
+
+# Extract Solr archive
+tar xfz "$SOLR_TAR" -C ..
+
+# Configure & start Solr
+cd ../solr-$SOLR_VERSION
 ./bin/solr start -force
 ./bin/solr create -c opus4 -force
 cd server/solr/opus4/conf/