diff --git a/.github/workflows/all-tests.yml b/.github/workflows/all-tests.yml
index 8241db95..7cb57b84 100644
--- a/.github/workflows/all-tests.yml
+++ b/.github/workflows/all-tests.yml
@@ -24,33 +24,15 @@ jobs:
       # check path to bundled Maven executable; it should be then used in ATLAS_MVN
       - run: mvn -version
 
-  prepare:
-    name: Prepare Matrix
-    runs-on: ubuntu-latest
-    outputs:
-      unit-tests-matrix: ${{ steps.set-matrix.outputs.unit-tests-matrix }}
-      jira-it-matrix: ${{ steps.set-matrix.outputs.jira-it-matrix }}
-      confluence-it-matrix: ${{ steps.set-matrix.outputs.confluence-it-matrix }}
-      bitbucket-it-matrix: ${{ steps.set-matrix.outputs.bitbucket-it-matrix }}
-      # TODO: Remove these flags when new major jira (10.x) and bitbucket (9.x) are released
-      skip-jira-its: ${{ steps.set-matrix.outputs.skip-jira-its }}
-      skip-bitbucket-its: ${{ steps.set-matrix.outputs.skip-bitbucket-its }}
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          ref: ${{ github.event.inputs.ref }}
-      - id: set-matrix
-        run: bin/build/prepare-matrices.sh
-
   unit-tests:
     name: Unit Tests
-    needs: prepare
     runs-on: ubuntu-20.04
     # around 800 Mb of dependencies need to be loaded; it may take long first time until it's cached
     timeout-minutes: 30
     if: "(github.event.inputs.jobs == '' || contains(github.event.inputs.jobs, 'unit-tests')) && !contains(github.event.head_commit.message, '[skip ci]')"
     strategy:
-      matrix: ${{ fromJSON(needs.prepare.outputs.unit-tests-matrix) }}
+      matrix:
+        java-version: [8, 11]
       fail-fast: false
     steps:
       - uses: actions/checkout@v4
@@ -76,10 +58,16 @@ jobs:
     name: Jira
     runs-on: ubuntu-20.04
     timeout-minutes: 30
-    if: (github.event.inputs.jobs == '' || contains(github.event.inputs.jobs, 'integration-tests-jira')) && !needs.prepare.outputs.skip-jira-its
-    needs: [prepare, unit-tests]
+    if: github.event.inputs.jobs == '' || contains(github.event.inputs.jobs, 'integration-tests-jira')
+    needs: unit-tests
     strategy:
-      matrix: ${{ fromJSON(needs.prepare.outputs.jira-it-matrix) }}
+      matrix:
+        java-version: [8, 11, 17]
+        jira-version: [8.15.0, 9.5.0]
+        # Java 17 support is added only since Jira 9.5: https://confluence.atlassian.com/jiracore/preparing-for-jira-9-5-1167834011.html
+        exclude:
+          - java-version: 17
+            jira-version: 8.15.0
       fail-fast: false
     steps:
       - uses: actions/checkout@v4
@@ -113,9 +101,17 @@ jobs:
     runs-on: ubuntu-20.04
     timeout-minutes: 30
     if: github.event.inputs.jobs == '' || contains(github.event.inputs.jobs, 'integration-tests-confluence')
-    needs: [prepare, unit-tests]
+    needs: unit-tests
     strategy:
-      matrix: ${{ fromJSON(needs.prepare.outputs.confluence-it-matrix) }}
+      matrix:
+        # every version part should be 0 <= <version> <= 255; otherwise Confluence fails to start
+        java-version: [8, 11, 17]
+        confluence-version: [7.10.0, 8.0.0]
+        exclude:
+          - java-version: 8
+            confluence-version: 8.0.0 # Confluence 8 doesn't support Java 8 anymore
+          - java-version: 17
+            confluence-version: 7.10.0
       fail-fast: false
     steps:
       - uses: actions/checkout@v4
@@ -148,10 +144,16 @@ jobs:
     name: Bitbucket
     runs-on: ubuntu-20.04
     timeout-minutes: 30
-    if: (github.event.inputs.jobs == '' || contains(github.event.inputs.jobs, 'integration-tests-bitbucket')) && !needs.prepare.outputs.skip-bitbucket-its
-    needs: [prepare, unit-tests]
+    if: github.event.inputs.jobs == '' || contains(github.event.inputs.jobs, 'integration-tests-bitbucket')
+    needs: unit-tests
     strategy:
-      matrix: ${{ fromJSON(needs.prepare.outputs.bitbucket-it-matrix) }}
+      matrix:
+        java-version: [8, 11, 17]
+        bitbucket-version: [7.6.0, 8.8.0]
+        # Bitbucket 8.8.0 is the first one that supports Java 17
+        exclude:
+          - java-version: 17
+            bitbucket-version: 7.6.0
       fail-fast: false
     steps:
       - uses: actions/checkout@v4
diff --git a/bin/build/get-plugin-major-version.sh b/bin/build/get-plugin-major-version.sh
deleted file mode 100755
index 67664922..00000000
--- a/bin/build/get-plugin-major-version.sh
+++ /dev/null
@@ -1,30 +0,0 @@
-#!/usr/bin/env bash
-
-# INPUT ENV VARS
-version_type="${1:?Please set pass a version type. Examples: 'jira', 'confluence', 'bitbucket' or 'common'}"
-# [-SNAPSHOT] part prevents matching version in a [parent] section
-version_pattern='<version>[0-9]+\.[0-9]+\.[0-9]+-SNAPSHOT</version>'
-
-case $version_type in
-  jira)
-    pl_path='jira-slack-server-integration/jira-slack-server-integration-plugin/pom.xml'
-    ;;
-  confluence)
-    pl_path='confluence-slack-integration/confluence-slack-server-integration-plugin/pom.xml'
-    ;;
-  bitbucket)
-    pl_path='bitbucket-slack-server-integration-plugin/pom.xml'
-    ;;
-  common)
-    pl_path='pom.xml'
-    version_pattern='<version>[0-9]+\.[0-9]+\.[0-9]+</version>'
-    ;;
-  *)
-    echo "Invalid version type"
-    exit 1
-    ;;
-esac
-
-SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
-pl_version=$(cat "$SCRIPT_DIR/../../$pl_path" | grep -oE -m 1 $version_pattern | grep -oE '[0-9]+\.[0-9]+\.[0-9]+')
-echo "${pl_version%.*.*}"
\ No newline at end of file
diff --git a/bin/build/java-product-matrix.json b/bin/build/java-product-matrix.json
deleted file mode 100644
index 781228e1..00000000
--- a/bin/build/java-product-matrix.json
+++ /dev/null
@@ -1,58 +0,0 @@
-{
-  "current": {
-    "unit-tests": {
-      "java-version": ["17"]
-    },
-    "jira-it": {
-      "java-version": ["17"],
-      "jira-version": ["10.0.0"]
-    },
-    "confluence-it": {
-      "java-version": ["17"],
-      "confluence-version": ["9.0.0-m81"]
-    },
-    "bitbucket-it": {
-      "java-version": ["17"],
-      "bitbucket-version": ["9.0.0"]
-    }
-  },
-  "old": {
-    "unit-tests": {
-      "java-version": ["8", "11"]
-    },
-    "jira-it": {
-      "java-version": ["8", "11", "17"],
-      "jira-version": ["8.15.0", "9.5.0"],
-      "exclude": [
-        {
-          "java-version": "17",
-          "jira-version": "8.15.0"
-        }
-      ]
-    },
-    "confluence-it": {
-      "java-version": ["8", "11", "17"],
-      "confluence-version": ["7.10.0", "8.0.0"],
-      "exclude": [
-        {
-          "java-version": "8",
-          "confluence-version": "8.0.0"
-        },
-        {
-          "java-version": "17",
-          "confluence-version": "7.10.0"
-        }
-      ]
-    },
-    "bitbucket-it": {
-      "java-version": ["8", "11", "17"],
-      "bitbucket-version": ["7.6.0", "8.8.0"],
-      "exclude": [
-        {
-          "java-version": "17",
-          "bitbucket-version": "7.6.0"
-        }
-      ]
-    }
-  }
-}
\ No newline at end of file
diff --git a/bin/build/prepare-matrices.sh b/bin/build/prepare-matrices.sh
deleted file mode 100755
index 200a3f17..00000000
--- a/bin/build/prepare-matrices.sh
+++ /dev/null
@@ -1,20 +0,0 @@
-#!/usr/bin/env bash
-
-matrix_file='bin/build/java-product-matrix.json'
-
-# Get slack plugin major common version
-pl_common_version=$(. bin/build/get-plugin-major-version.sh common)
-if [ $pl_common_version -gt 1 ]; then
-  matrix_key='current'
-# TODO: Remove these flags when new major jira (10.x) and bitbucket (9.x) are released
-  echo "skip-jira-its=true" >> $GITHUB_OUTPUT
-  echo "skip-bitbucket-its=true" >> $GITHUB_OUTPUT
-else
-  matrix_key='old'
-fi
-echo "Matrix key - $matrix_key"
-
-echo "unit-tests-matrix=$(jq --compact-output --arg v "$matrix_key" '.[$v]."unit-tests"' $matrix_file)" >> $GITHUB_OUTPUT
-echo "jira-it-matrix=$(jq --compact-output --arg v "$matrix_key" '.[$v]."jira-it"' $matrix_file)" >> $GITHUB_OUTPUT
-echo "confluence-it-matrix=$(jq --compact-output --arg v "$matrix_key" '.[$v]."confluence-it"' $matrix_file)" >> $GITHUB_OUTPUT
-echo "bitbucket-it-matrix=$(jq --compact-output --arg v "$matrix_key" '.[$v]."bitbucket-it"' $matrix_file)" >> $GITHUB_OUTPUT
\ No newline at end of file
diff --git a/bin/release-check/check-release.sh b/bin/release-check/check-release.sh
index 5d870d75..b36ae1e4 100755
--- a/bin/release-check/check-release.sh
+++ b/bin/release-check/check-release.sh
@@ -48,21 +48,19 @@ echo "Determined workflow name: $workflow_name"
 
 # RUN TESTS AGAINST SPECIFIC VERSIONS
 workflow_links=()
-pl_common_version=$(. ../build/get-plugin-major-version.sh common)
-if [ $pl_common_version -eq 1 ]; then
-  if [ $product_type != "confluence" ]; then
-    echo "Running workflow with params: workflow-name=$workflow_name java-version=8.0.252 product-version=$product_version"
-    first_workflow_link=$(start_workflow $workflow_name 8.0.252 $product_version)
-    echo "Pipeline URL: $first_workflow_link"
-    workflow_links+=("$first_workflow_link")
-  fi
-
-  echo "Running workflow with params: workflow-name=$workflow_name java-version=11 product-version=$product_version"
-  second_workflow_link=$(start_workflow $workflow_name 11 $product_version)
-  echo "Pipeline URL: $second_workflow_link"
-  workflow_links+=("$second_workflow_link")
+# Confluence 8+ does not support Java 8
+if [ $product_type != "confluence" ]; then
+  echo "Running workflow with params: workflow-name=$workflow_name java-version=8.0.252 product-version=$product_version"
+  first_workflow_link=$(start_workflow $workflow_name 8.0.252 $product_version)
+  echo "Pipeline URL: $first_workflow_link"
+  workflow_links+=("$first_workflow_link")
 fi
 
+echo "Running workflow with params: workflow-name=$workflow_name java-version=11 product-version=$product_version"
+second_workflow_link=$(start_workflow $workflow_name 11 $product_version)
+echo "Pipeline URL: $second_workflow_link"
+workflow_links+=("$second_workflow_link")
+
 echo "Running workflow with params: workflow-name=$workflow_name java-version=17 product-version=$product_version"
 third_workflow_link=$(start_workflow $workflow_name 17 $product_version)
 echo "Pipeline URL: $third_workflow_link"
diff --git a/bin/release-check/plugin-product-compat-matrix.json b/bin/release-check/plugin-product-compat-matrix.json
deleted file mode 100644
index 931dc794..00000000
--- a/bin/release-check/plugin-product-compat-matrix.json
+++ /dev/null
@@ -1,14 +0,0 @@
-{
-  "jira": {
-    "3": "[0-9]\\.[0-9]+\\.[0-9]+",
-    "4": "10\\.[0-9]+\\.[0-9]+"
-  },
-  "confluence": {
-    "3": "[0-8]\\.[0-9]+\\.[0-9]+",
-    "4": "9\\.[0-9]+\\.[0-9]+"
-  },
-  "bitbucket": {
-    "4": "[0-8]\\.[0-9]+\\.[0-9]+",
-    "5": "9\\.[0-9]+\\.[0-9]+"
-  }
-}
\ No newline at end of file
diff --git a/bin/release-check/run-product-release-check.sh b/bin/release-check/run-product-release-check.sh
index 4ffb0c5a..53302dc3 100755
--- a/bin/release-check/run-product-release-check.sh
+++ b/bin/release-check/run-product-release-check.sh
@@ -12,22 +12,8 @@ if [ "$latest_releases" = "" ]; then
   exit
 fi
 
-# TAKE AND CHECKS LATEST COMPATIBLE VERSION ONLY, MEANING THE GREATEST REVISION VERSION
-pl_product_version=$(. ../get-plugin-major-version.sh "$PRODUCT")
-product_compat_version_regex=$(jq -r --arg pl "$pl_product_version" --arg p "$PRODUCT" '.[$p].[$pl]' ./plugin-product-compat-matrix.json)
-latest_version=$(echo "$latest_releases" | grep -oE "$product_compat_version_regex" | tail -1)
-
-if [ "$latest_version" = "" ]; then
-  echo "Could not find latest versions"
-  echo "Product [$PRODUCT]"
-  echo "Compatible version pattern [$product_compat_version_regex]"
-  exit
-fi
-
-echo "========================"
-echo "LATEST VERSION"
-echo "$latest_version"
-echo "========================"
+# TAKE AND CHECKS LATEST VERSION ONLY, MEANING THE GREATEST REVISION VERSION
+latest_version=$(echo "$latest_releases" | tail -1)
 
 # RUN CHECK FOR LATEST VERSION
 PRODUCT_VERSION="$latest_version" . ./check-release.sh