diff --git a/check-compatibility.sh b/check-compatibility.sh
new file mode 100755
index 0000000..545f99f
--- /dev/null
+++ b/check-compatibility.sh
@@ -0,0 +1,60 @@
+#!/bin/bash
+
+export PGUSER=postgres
+
+DBNAME=crankshaft_compatcheck
+
+function die {
+    echo $1
+    exit -1
+}
+
+# Create fresh DB
+psql -c "CREATE DATABASE $DBNAME;" || die "Could not create DB"
+
+# Hook for cleanup
+function cleanup {
+    psql -c "DROP DATABASE IF EXISTS crankshaft_compatcheck;"
+}
+trap cleanup EXIT
+
+# Deploy previous release
+(cd src/py && sudo make deploy RUN_OPTIONS="--no-deps") || die "Could not deploy python extension"
+(cd src/pg && sudo make deploy) || die " Could not deploy last release"
+psql -c "SELECT * FROM pg_available_extension_versions WHERE name LIKE 'crankshaft';"
+
+# Install in the fresh DB
+psql $DBNAME <<'EOF'
+-- Install dependencies
+CREATE EXTENSION plpythonu;
+CREATE EXTENSION postgis VERSION '2.2.2';
+
+-- Create role publicuser if it does not exist
+DO
+$$
+BEGIN
+   IF NOT EXISTS (
+      SELECT *
+      FROM   pg_catalog.pg_user
+      WHERE  usename = 'publicuser') THEN
+
+      CREATE ROLE publicuser LOGIN;
+   END IF;
+END
+$$ LANGUAGE plpgsql;
+
+-- Install the default version
+CREATE EXTENSION crankshaft;
+\dx
+EOF
+
+# TODO save public functions and signatures
+
+# Check it can be upgraded
+psql $DBNAME -c "ALTER EXTENSION crankshaft update to 'dev';" || die "Cannot upgrade to dev version"
+
+
+
+# TODO check against saved public functions and signatures
+
+