diff --git a/polkadot/scripts/gitlab/check_runtime.sh b/polkadot/scripts/gitlab/check_runtime.sh
index cdb7538d1f..bd14abde3e 100755
--- a/polkadot/scripts/gitlab/check_runtime.sh
+++ b/polkadot/scripts/gitlab/check_runtime.sh
@@ -1,18 +1,39 @@
 #!/bin/sh
 #
 #
-# check for any changes in the ^runtime/ tree. if there are any changes found, 
-# it should mark the PR B2-breaksapi and "auto-fail" the PR if there 
-# isn't a change in the runtime/{kusama,polkadot}/src/lib.rs file that alters 
-# the version.
+# check for any changes in the ^runtime/ tree. if there are no changes check
+# if the substrate reference in the Cargo.lock has been changed. If so pull
+# the repo and verify if the {spec,impl}_version s have been altered since the
+# last reference. If there were changes the script will continue to check if
+# the spec_version resp impl_version of polkadot have been altered as well.
+# this will also be checked if there were changes to the runtime source files.
+#
+# If there are any changes found, it will mark the PR breaksapi and
+# "auto-fail" the PR if there isn't a change in the
+# runtime/{polkadot,kusama}/src/lib.rs file
+# that alters the version since the last release tag.
+
 
 set -e # fail on any error
 
 
-# give some context
+SUBSTRATE_REPO="https://github.com/paritytech/substrate"
+SUBSTRATE_REPO_CARGO="git\+${SUBSTRATE_REPO}\?branch=polkadot-master"
+SUBSTRATE_VERSIONS_FILE="bin/node/runtime/src/lib.rs"
+
+boldprint () { printf "|\n| \033[1m${@}\033[0m\n|\n" ; }
+boldcat () { printf "|\n"; while read l; do printf "| \033[1m${l}\033[0m\n"; done; printf "|\n" ; }
+
+
+# figure out the latest release tag
+LATEST_TAG="$(git tag -l | sort -V | tail -n 1)"
+boldprint "latest release tag ${LATEST_TAG}"
+
+
+boldprint "latest 10 commits of ${CI_COMMIT_REF_NAME}"
 git log --graph --oneline --decorate=short -n 10
 
-# make sure the master branch is available in shallow clones
+boldprint "make sure the master branch is available in shallow clones"
 git fetch --depth=${GIT_DEPTH:-100} origin master
 
 
@@ -29,84 +50,128 @@ github_label () {
 }
 
 
+boldprint "check if the wasm sources changed since ${LATEST_TAG}"
+if ! git diff --name-only refs/tags/${LATEST_TAG}...${CI_COMMIT_SHA} \
+	| grep -q -e '^runtime/'
+then
+	boldprint "no changes to the polkadot runtime source code detected"
+	# continue checking if Cargo.lock was updated with a new substrate reference
+	# and if that change includes a {spec|impl}_version update.
+
+	SUBSTRATE_REFS_CHANGED="$(git diff refs/tags/${LATEST_TAG}...${CI_COMMIT_SHA} Cargo.lock \
+		| sed -n -r "s~^[\+\-]source = \"${SUBSTRATE_REPO_CARGO}#([a-f0-9]+)\".*$~\1~p" | sort -u | wc -l)"
+
+	# check Cargo.lock for substrate ref change
+	case "${SUBSTRATE_REFS_CHANGED}" in
+	  (0)
+	    boldprint "substrate refs not changed in Cargo.lock"
+	    exit 0
+	    ;;
+	  (2)
+	    boldprint "substrate refs updated since ${LATEST_TAG}"
+	    ;;
+	  (*)
+	    boldprint "check unsupported: more than one commit targeted in repo ${SUBSTRATE_REPO_CARGO}"
+	    exit 1
+	esac
+
+
+	SUBSTRATE_PREV_REF="$(git diff refs/tags/${LATEST_TAG}...${CI_COMMIT_SHA} Cargo.lock \
+		| sed -n -r "s~^\-source = \"${SUBSTRATE_REPO_CARGO}#([a-f0-9]+)\".*$~\1~p" | sort -u | head -n 1)"
+
+	SUBSTRATE_NEW_REF="$(git diff refs/tags/${LATEST_TAG}...${CI_COMMIT_SHA} Cargo.lock \
+		| sed -n -r "s~^\+source = \"${SUBSTRATE_REPO_CARGO}#([a-f0-9]+)\".*$~\1~p" | sort -u | head -n 1)"
+
+
+	boldcat <<-EOT
+	previous substrate commit id ${SUBSTRATE_PREV_REF}
+	new substrate commit id      ${SUBSTRATE_NEW_REF}
+	EOT
+
+	# okay so now need to fetch the substrate repository and check whether spec_version or impl_version has changed there
+	SUBSTRATE_CLONE_DIR="$(mktemp -t -d substrate-XXX)"
+	trap "rm -rf ${SUBSTRATE_CLONE_DIR}" INT QUIT TERM ABRT EXIT
+
+
+	git clone --branch polkadot-master --depth 100 --no-tags \
+	  ${SUBSTRATE_REPO} ${SUBSTRATE_CLONE_DIR}
+
+
+	# check if there are changes to the spec|impl versions
+	git -C ${SUBSTRATE_CLONE_DIR} diff \
+		${SUBSTRATE_PREV_REF}..${SUBSTRATE_NEW_REF} ${SUBSTRATE_VERSIONS_FILE} \
+		| grep -E '^[\+\-][[:space:]]+(spec|impl)_version: +([0-9]+),$' || exit 0
+
+	boldcat <<-EOT
+	spec_version or or impl_version have changed in substrate after updating Cargo.lock
+	please make sure versions are bumped in polkadot accordingly
+	EOT
+fi
+
+
 # Introduce runtime/polkadot/src/lib.rs once Polkadot mainnet is live.
-for VERSIONS_FILE in runtime/kusama/src/lib.rs 
+for VERSIONS_FILE in runtime/kusama/src/lib.rs
 do
-	# check if the wasm sources changed
-	if ! git diff --name-only origin/master...${CI_COMMIT_SHA} \
-		| grep -q -e '^runtime/'
-	then
-		cat <<-EOT
-		
-		no changes to the runtime source code detected
-	
-		EOT
-	
-		continue
-	fi
-	
-	
-	
 	# check for spec_version updates: if the spec versions changed, then there is
 	# consensus-critical logic that has changed. the runtime wasm blobs must be
 	# rebuilt.
-	
-	add_spec_version="$(git diff origin/master...${CI_COMMIT_SHA} ${VERSIONS_FILE} \
+
+	add_spec_version="$(git diff refs/tags/${LATEST_TAG}...${CI_COMMIT_SHA} ${VERSIONS_FILE} \
 		| sed -n -r "s/^\+[[:space:]]+spec_version: +([0-9]+),$/\1/p")"
-	sub_spec_version="$(git diff origin/master...${CI_COMMIT_SHA} ${VERSIONS_FILE} \
+	sub_spec_version="$(git diff refs/tags/${LATEST_TAG}...${CI_COMMIT_SHA} ${VERSIONS_FILE} \
 		| sed -n -r "s/^\-[[:space:]]+spec_version: +([0-9]+),$/\1/p")"
-	
-	
+
+
 	# see if the version and the binary blob changed
 	if [ "${add_spec_version}" != "${sub_spec_version}" ]
 	then
-	
+
 		github_label "B2-breaksapi"
-	
-		cat <<-EOT
-			
+
+		boldcat <<-EOT
+
 			changes to the runtime sources and changes in the spec version.
-		
+
 			spec_version: ${sub_spec_version} -> ${add_spec_version}
-		
+
 		EOT
 		continue
-	
+
 	else
 		# check for impl_version updates: if only the impl versions changed, we assume
 		# there is no consensus-critical logic that has changed.
-	
-		add_impl_version="$(git diff origin/master...${CI_COMMIT_SHA} ${VERSIONS_FILE} \
+
+		add_impl_version="$(git diff refs/tags/${LATEST_TAG}...${CI_COMMIT_SHA} ${VERSIONS_FILE} \
 			| sed -n -r 's/^\+[[:space:]]+impl_version: +([0-9]+),$/\1/p')"
-		sub_impl_version="$(git diff origin/master...${CI_COMMIT_SHA} ${VERSIONS_FILE} \
+		sub_impl_version="$(git diff refs/tags/${LATEST_TAG}...${CI_COMMIT_SHA} ${VERSIONS_FILE} \
 			| sed -n -r 's/^\-[[:space:]]+impl_version: +([0-9]+),$/\1/p')"
-	
-	
+
+
 		# see if the impl version changed
 		if [ "${add_impl_version}" != "${sub_impl_version}" ]
 		then
-			cat <<-EOT
-			
+			boldcat <<-EOT
+
 			changes to the runtime sources and changes in the impl version.
-	
+
 			impl_version: ${sub_impl_version} -> ${add_impl_version}
-	
+
 			EOT
 			continue
 		fi
-	
-	
-		cat <<-EOT
-	
-		wasm source files changed but not the spec/impl version and the runtime
-		binary blob. If changes made do not alter logic, just bump 'impl_version'.
-		If they do change logic, bump 'spec_version' and rebuild wasm.
-	
+
+
+		boldcat <<-EOT
+		wasm source files changed or the spec version in the substrate reference in
+		the Cargo.lock but not the spec/impl version. If changes made do not alter
+		logic, just bump 'impl_version'. If they do change logic, bump
+		'spec_version'.
+
 		source file directories:
 		- runtime
-	
+
 		versions file: ${VERSIONS_FILE}
-	
+
 		EOT
 
 		exit 1