diff --git a/README.mz b/README.mz
index 3e18954..25a2cc7 100644
--- a/README.mz
+++ b/README.mz
@@ -442,8 +442,8 @@ We also care about code coverage so we'll use [nyc][8] to generate a coverage
 report.
 
 ```bash bash -eo pipefail
-# Install and prune dependencies
-{ npm i && npm prune; } &> /dev/null
+# Clearn install dependencies.
+npm ci &> /dev/null
 
 # Run tests and generate a coverage report
 npx nyc npm t | npx tap-nyc
diff --git a/src/index.test.js b/src/index.test.js
index c74c18a..ed2a7f7 100755
--- a/src/index.test.js
+++ b/src/index.test.js
@@ -1,5 +1,7 @@
 const { test } = require('tape')
+const { isNil } = require('./helpers')
 const { check, gen } = require('tape-check')
+const { version } = require('../package')
 const {
   reference,
   instanceOf,
@@ -166,3 +168,15 @@ test('Deprecated functions', ts => {
   console.error = consoleError
   ts.end()
 })
+
+if (version.startsWith('2')) {
+
+  test('Deprecated functions in version 2', t => {
+    t.plan(3)
+    t.ok(isNil(require('./index').typed))
+    t.ok(isNil(require('./index').t))
+    t.ok(isNil(require('./index').ref))
+  })
+
+}
+