diff --git a/.github/workflows/vm-pr.yml b/.github/workflows/vm-pr.yml
index da81a09d0c..35e796b903 100644
--- a/.github/workflows/vm-pr.yml
+++ b/.github/workflows/vm-pr.yml
@@ -39,7 +39,7 @@ jobs:
         working-directory: ${{github.workspace}}
 
       - run: npm run coverage
-      
+
       - uses: codecov/codecov-action@v1
         with:
           file: ${{ env.cwd }}/coverage/lcov.info
@@ -48,7 +48,7 @@ jobs:
       - run: npm run test:API
       - run: npm run test:API:browser
       - run: npm run lint
-  
+
   vm-state:
     runs-on: ubuntu-latest
     strategy:
@@ -131,9 +131,9 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        # Args to pass to the tester. Note that some have splitted the slow tests and only 
+        # Args to pass to the tester. Note that some have splitted the slow tests and only
         #   running those: these are only on forks where that is applicable (see PR #489 for numbers on these)
-        
+
         # Tests were splitted with --dir and --excludeDir to balance execution times below the 9min mark.
         args: [
           '--fork=Istanbul --dir=GeneralStateTests/stTimeConsuming --expected-test-amount=15561',
@@ -171,9 +171,9 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        # Args to pass to the tester. Note that some have splitted the slow tests and only 
+        # Args to pass to the tester. Note that some have splitted the slow tests and only
         #   running those: these are only on forks where that is applicable (see PR #489 for numbers on these)
-        
+
         # Tests were splitted with --dir and --excludeDir to balance execution times below the 9min mark.
         args: [
           '--fork=Berlin --expected-test-amount=33',
@@ -212,6 +212,37 @@ jobs:
 
       - run: npm run test:blockchain -- ${{ matrix.args }}
 
+  vm-backwards-compatibility:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/setup-node@v1
+        with:
+          node-version: 12.x
+      - uses: actions/checkout@v2
+        with:
+          submodules: recursive
+
+      - name: Dependency cache
+        uses: actions/cache@v2
+        id: cache
+        with:
+          key: VM-${{ runner.os }}-12-${{ hashFiles('**/package-lock.json') }}
+          path: '**/node_modules'
+
+      # Installs root dependencies, ignoring Bootstrap All script.
+      # Bootstraps the current package only
+      - run: npm install --ignore-scripts && npm run bootstrap:vm
+        if: steps.cache.outputs.cache-hit != 'true'
+        working-directory: ${{github.workspace}}
+
+      # Builds current package and the ones it depends from.
+      - run: npm run build:vm
+        working-directory: ${{github.workspace}}
+
+      # Runs vm test:API with @ethereumjs/tx@3.0.2
+      - run: npm run check:compatibility -- -t vm -d tx -n @ethereumjs/tx -v "3.0.2" -s test:API
+        working-directory: ${{github.workspace}}
+
   vm-benchmarks:
     runs-on: ubuntu-latest
     steps:
diff --git a/package.json b/package.json
index f98166f1dc..1f32f386fe 100644
--- a/package.json
+++ b/package.json
@@ -39,6 +39,7 @@
     "test": "lerna exec npm run test --parallel",
     "coverage": "lerna run coverage --stream",
     "docs:build": "lerna run docs:build --ignore @ethereumjs/ethash",
-    "clean": "rm -rf node_modules packages/*/node_modules packages/*/test-build packages/*/dist packages/*/dist.browser packages/*/package-lock.json"
+    "clean": "rm -rf node_modules packages/*/node_modules packages/*/test-build packages/*/dist packages/*/dist.browser packages/*/package-lock.json",
+    "check:compatibility": "bash ./scripts/check-compatibility.sh"
   }
 }
diff --git a/scripts/check-compatibility.sh b/scripts/check-compatibility.sh
new file mode 100755
index 0000000000..b77613e66c
--- /dev/null
+++ b/scripts/check-compatibility.sh
@@ -0,0 +1,92 @@
+#!/usr/bin/env bash
+
+# --------------------------------------------------------------------------------------------------
+# A script to test the backwards compatibility of monorepo packages
+# with previously published monorepo package sub dependencies.
+#
+# Substitutes a current package with another version of it installed from npm
+# and runs the tests of a package which consumes it.
+#
+# The monorepo is restored to orignal state after script completes, so this script
+# can be run repeatedly for different scenarios in CI
+#
+# # USAGE
+# -t <test> the monorepo package whose tests we'd like to run (ex: vm)
+# -d <dependency> the monorepo package dependency we want to swap out (ex: tx)
+# -n <npm>    the npm package name to swap in (ex: @ethereumjs/tx)
+# -v <version> the npm package version to swap in (ex: 3.0.2)
+# -s <script> the script to "npm run" to execute the tests
+# --------------------------------------------------------------------------------------------------
+
+# Exit immediately on error
+set -o errexit
+
+if [ -z "$CI" ]; then
+
+  echo "=================================================================="
+  echo "This script temporarily alters your deps and might mess things up."
+  echo "Only run in CI or locally with 'CI=true'                          "
+  echo "=================================================================="
+
+  exit 1
+
+fi
+
+# Collect command arguments
+while getopts t:d:n:v:s: flag
+do
+    case "${flag}" in
+        t) tst=${OPTARG};;
+        d) dep=${OPTARG};;
+        n) npm=${OPTARG};;
+        v) ver=${OPTARG};;
+        s) scr=${OPTARG};;
+    esac
+done
+
+[ -z $tst ] && echo "Missing -t <test> argument" && exit 1
+[ -z $dep ] && echo "Missing -d <dependency> argument" && exit 1
+[ -z $npm ] && echo "Missing -n <npm> argument" && exit 1
+[ -z $ver ] && echo "Missing -v <version> argument" && exit 1
+[ -z $scr ] && echo "Missing -s <script> argument" && exit 1
+
+echo ">> Stashing packages/${dep} in 'stash/'"
+
+mkdir stash
+mv packages/${dep} stash
+
+echo ">> Installing and staging ${npm}@${ver}"
+
+mkdir ${dep}
+cd ${dep}
+npm init --yes
+npm install ${npm}@${ver}
+mv node_modules/${npm}/* .
+
+# Comment out by default: Injects a log line into the npm installed
+# package to verify that the substitute package is *actually* swapped in
+# for the targets tests (by looking at terminal output)
+#
+# echo ">> Injecting verification log line into line 21 of tx/dist/transaction.js"
+#
+# sed -i -e $'21 a\\\n'"console.log('>>>>> HELLO!!');"  ./dist/transaction.js
+
+echo ">> Swapping packages/${dep} with ${npm}@${ver} and re-linking"
+
+cd ..
+mv ${dep} packages
+lerna link
+
+echo ">> Executing 'npm run ${scr}' in packages/${tst}"
+
+cd packages/${tst}
+npm run ${scr}
+cd ../..
+
+echo ">> Un-stashing and relinking packages/${dep}"
+
+rm -rf packages/${dep}
+mv stash/${dep} packages
+rm -rf stash
+rm -rf ${dep}
+lerna link