diff --git a/db/builder_db.ml b/db/builder_db.ml
index 63fbeac..f2950b7 100644
--- a/db/builder_db.ml
+++ b/db/builder_db.ml
@@ -4,7 +4,8 @@ open Caqti_request.Infix
 
 let application_id = 1234839235l
 
-(* Please update this when making changes! *)
+(* Please update this when making changes! And also update
+   packaging/batch-viz.sh and packaging/visualizations.sh. *)
 let current_version = 18L
 
 type 'a id = 'a Rep.id
diff --git a/packaging/batch-viz.sh b/packaging/batch-viz.sh
index 95236c3..bc2ae3b 100755
--- a/packaging/batch-viz.sh
+++ b/packaging/batch-viz.sh
@@ -77,6 +77,8 @@ done
 DB="${DATA_DIR}/builder.sqlite3"
 [ ! -e "$DB" ] && die "The database doesn't exist: '$DB'"
 
+# Let's be somewhat lenient with the database version.
+# In visualizations.sh we can be more strict.
 DB_VERSION="$(sqlite3 "$DB" "PRAGMA user_version;")"
 [ -z "$DB_VERSION" ] && die "Couldn't read database version from '$DB'"
 [ "$DB_VERSION" -lt 16 ] && die "The database version should be >= 16. It is '$DB_VERSION'"
diff --git a/packaging/visualizations.sh b/packaging/visualizations.sh
index 5e575df..50c99d9 100755
--- a/packaging/visualizations.sh
+++ b/packaging/visualizations.sh
@@ -74,6 +74,16 @@ info "processing UUID '${UUID}'"
 
 DB="${DATA_DIR}/builder.sqlite3"
 
+# A new visualizations.sh script may be installed during an upgrade while the
+# old builder-web binary is running. In that case things can get out of sync.
+DB_VERSION="$(sqlite3 "$DB" "PRAGMA user_version;")"
+[ -z "$DB_VERSION" ] && die "Couldn't read database version from '$DB'"
+[ "$DB_VERSION" -ne 18 ] && die "The database version should be 18. It is '$DB_VERSION'"
+
+APP_ID="$(sqlite3 "$DB" "PRAGMA application_id;")"
+[ -z "$APP_ID" ] && die "Couldn't read application-id from '$DB'"
+[ "$APP_ID" -ne 1234839235 ] && die "The application-id should be 1234839235. It is '$APP_ID'"
+
 get_main_binary () {
     sqlite3 "${DB}" "SELECT '_artifacts/' || substr(lower(hex(ba.sha256)), 1, 2) || '/' || lower(hex(ba.sha256))
         FROM build AS b