diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index ebbdcbd767cc0685c6619e05169a89d595a6c591..ead290b6ec091e5406622af7b6e9a877d86f03be 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -15,7 +15,7 @@ default:
   tags:
     - gitlab-org
 
-image: node:14-slim
+image: node:12-slim
 
 stages:
   - test
diff --git a/.tool-versions b/.tool-versions
index d11b5698a0e52324e564f859ae08295ed1dc2f61..ce9317466475741e94d84af7b167e46b3744928d 100644
--- a/.tool-versions
+++ b/.tool-versions
@@ -1 +1 @@
-nodejs 14.16.0
+nodejs 12.20.0
diff --git a/tsconfig.json b/tsconfig.json
index a6bb192fe9c14a6897aca062bb732c0a4a0d53e6..939977423bdbde2edc48340d1546624ceb40d9fc 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -1,10 +1,10 @@
 {
   "compilerOptions": {
     "module": "commonjs",
-    "target": "es2020",
+    "target": "es6",
     "outDir": "out",
     // we need to include dom library for msw to work, see https://github.com/mswjs/msw/issues/408
-    "lib": ["es2020", "dom"],
+    "lib": ["es6", "dom"],
     "allowJs": true,
     "resolveJsonModule": true,
     "skipLibCheck": true,