diff --git a/package-lock.json b/package-lock.json
index f77485aa5..294bc4709 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "io-ts",
-  "version": "2.2.14",
+  "version": "2.2.15",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
@@ -2313,6 +2313,12 @@
         "ts-node": "^8.10.2"
       },
       "dependencies": {
+        "fp-ts": {
+          "version": "2.9.5",
+          "resolved": "https://registry.npmjs.org/fp-ts/-/fp-ts-2.9.5.tgz",
+          "integrity": "sha512-MiHrA5teO6t8zKArE3DdMPT/Db6v2GUt5yfWnhBTrrsVfeCJUUnV6sgFvjGNBKDmEMqVwRFkEePL7wPwqrLKKA==",
+          "dev": true
+        },
         "glob": {
           "version": "7.1.6",
           "resolved": "https://registry.npmjs.org/glob/-/glob-7.1.6.tgz",
@@ -3269,9 +3275,9 @@
       "dev": true
     },
     "fp-ts": {
-      "version": "2.9.5",
-      "resolved": "https://registry.npmjs.org/fp-ts/-/fp-ts-2.9.5.tgz",
-      "integrity": "sha512-MiHrA5teO6t8zKArE3DdMPT/Db6v2GUt5yfWnhBTrrsVfeCJUUnV6sgFvjGNBKDmEMqVwRFkEePL7wPwqrLKKA==",
+      "version": "2.5.0",
+      "resolved": "https://registry.npmjs.org/fp-ts/-/fp-ts-2.5.0.tgz",
+      "integrity": "sha512-xkC9ZKl/i2cU+8FAsdyLcTvPRXphp42FcK5WmZpB47VXb4gggC3DHlVDKNLdbC+U8zz6yp1b0bj0mZg0axmZYQ==",
       "dev": true
     },
     "fragment-cache": {
diff --git a/package.json b/package.json
index f949262ef..f904dc85d 100644
--- a/package.json
+++ b/package.json
@@ -39,7 +39,7 @@
   "homepage": "https://github.com/gcanti/io-ts",
   "dependencies": {},
   "peerDependencies": {
-    "fp-ts": "^2.0.0"
+    "fp-ts": "^2.5.0"
   },
   "devDependencies": {
     "@types/benchmark": "1.0.31",
@@ -54,7 +54,7 @@
     "dtslint": "github:gcanti/dtslint",
     "eslint": "^7.18.0",
     "fast-check": "^1.24.2",
-    "fp-ts": "^2.9.5",
+    "fp-ts": "^2.5.0",
     "import-path-rewrite": "github:gcanti/import-path-rewrite",
     "jest": "25.2.7",
     "mocha": "7.1.1",
diff --git a/scripts/FileSystem.ts b/scripts/FileSystem.ts
index 9e2c2c468..fa10d9f0f 100644
--- a/scripts/FileSystem.ts
+++ b/scripts/FileSystem.ts
@@ -1,5 +1,5 @@
-import * as TE from 'fp-ts/TaskEither'
-import { flow } from 'fp-ts/function'
+import * as TE from 'fp-ts/lib/TaskEither'
+import { flow } from 'fp-ts/lib/function'
 import * as fs from 'fs'
 import G from 'glob'
 
diff --git a/scripts/build.ts b/scripts/build.ts
index ba6ec6f59..eabd0eb52 100644
--- a/scripts/build.ts
+++ b/scripts/build.ts
@@ -1,9 +1,9 @@
 import * as path from 'path'
-import * as E from 'fp-ts/Either'
-import { pipe } from 'fp-ts/function'
-import * as RTE from 'fp-ts/ReaderTaskEither'
-import * as A from 'fp-ts/ReadonlyArray'
-import * as TE from 'fp-ts/TaskEither'
+import * as E from 'fp-ts/lib/Either'
+import { pipe } from 'fp-ts/lib/pipeable'
+import * as RTE from 'fp-ts/lib/ReaderTaskEither'
+import * as A from 'fp-ts/lib/ReadonlyArray'
+import * as TE from 'fp-ts/lib/TaskEither'
 import { FileSystem, fileSystem } from './FileSystem'
 import { run } from './run'
 
@@ -31,18 +31,15 @@ export const copyPackageJson: Build<void> = (C) =>
 export const FILES: ReadonlyArray<string> = ['CHANGELOG.md', 'LICENSE', 'README.md']
 
 export const copyFiles: Build<ReadonlyArray<void>> = (C) =>
-  pipe(
-    FILES,
-    A.traverse(TE.taskEither)((from) => C.copyFile(from, path.resolve(OUTPUT_FOLDER, from)))
-  )
+  A.readonlyArray.traverse(TE.taskEither)(FILES, (from) => C.copyFile(from, path.resolve(OUTPUT_FOLDER, from)))
 
-const traverse = A.traverse(TE.taskEither)
+const traverse = A.readonlyArray.traverse(TE.taskEither)
 
 export const makeModules: Build<void> = (C) =>
   pipe(
     C.glob(`${OUTPUT_FOLDER}/lib/*.js`),
     TE.map(getModules),
-    TE.chain(traverse(makeSingleModule(C))),
+    TE.chain((modules) => traverse(modules, makeSingleModule(C))),
     TE.map(() => undefined)
   )
 
diff --git a/scripts/pre-publish.ts b/scripts/pre-publish.ts
index c326efd04..01db9915c 100644
--- a/scripts/pre-publish.ts
+++ b/scripts/pre-publish.ts
@@ -1,7 +1,6 @@
-import { left } from 'fp-ts/TaskEither'
+import { left } from 'fp-ts/lib/TaskEither'
 import { run } from './run'
 
 const main = left(new Error('"npm publish" can not be run from root, run "npm run release" instead'))
 
 run(main)
-
diff --git a/scripts/release.ts b/scripts/release.ts
index 750f3eddd..418c37ffe 100644
--- a/scripts/release.ts
+++ b/scripts/release.ts
@@ -1,7 +1,7 @@
 import { run } from './run'
 import * as child_process from 'child_process'
-import { left, right } from 'fp-ts/Either'
-import * as TE from 'fp-ts/TaskEither'
+import { left, right } from 'fp-ts/lib/Either'
+import * as TE from 'fp-ts/lib/TaskEither'
 
 const DIST = 'dist'
 
diff --git a/scripts/run.ts b/scripts/run.ts
index 7629fe11d..6c259ef49 100644
--- a/scripts/run.ts
+++ b/scripts/run.ts
@@ -1,5 +1,5 @@
-import { fold } from 'fp-ts/Either'
-import { TaskEither } from 'fp-ts/TaskEither'
+import { fold } from 'fp-ts/lib/Either'
+import { TaskEither } from 'fp-ts/lib/TaskEither'
 
 export function run<A>(eff: TaskEither<Error, A>): void {
   eff()
diff --git a/test/Codec.ts b/test/Codec.ts
index cfc48d99b..8b228ee39 100644
--- a/test/Codec.ts
+++ b/test/Codec.ts
@@ -20,6 +20,18 @@ const codecInt: _.Codec<unknown, number, H.Int> = _.fromDecoder(H.decoderInt)
 
 const codecUndefined: _.Codec<unknown, undefined, undefined> = _.fromDecoder(H.decoderUndefined)
 
+export type Json = boolean | number | string | null | JsonArray | JsonRecord
+
+export interface JsonRecord {
+  readonly [key: string]: Json
+}
+
+export interface JsonArray extends ReadonlyArray<Json> {}
+
+export function parseJSON<E>(s: string, onError: (reason: unknown) => E): E.Either<E, Json> {
+  return E.tryCatch(() => JSON.parse(s), onError)
+}
+
 describe('Codec', () => {
   describe('Invariant', () => {
     it('imap', () => {
@@ -624,8 +636,8 @@ describe('Codec', () => {
       encode: (s) => Buffer.from(s).toString('base64')
     }
 
-    const Json: _.Codec<string, string, E.Json> = {
-      decode: (s) => E.parseJSON(s, () => D.error(s, 'Json')),
+    const Json: _.Codec<string, string, Json> = {
+      decode: (s) => parseJSON(s, () => D.error(s, 'Json')),
       encode: (a) => JSON.stringify(a)
     }
 
diff --git a/test/Eq.ts b/test/Eq.ts
index 6e74bfc71..a7b1921bb 100644
--- a/test/Eq.ts
+++ b/test/Eq.ts
@@ -44,7 +44,7 @@ describe('Eq', () => {
   })
 
   it('intersect', () => {
-    const eq = pipe(E.type({ a: E.string }), E.intersect(E.type({ b: E.number })))
+    const eq = pipe(E.struct({ a: E.string }), E.intersect(E.struct({ b: E.number })))
     assert.deepStrictEqual(eq.equals({ a: 'a', b: 1 }, { a: 'a', b: 1 }), true)
     assert.deepStrictEqual(eq.equals({ a: 'a', b: 1 }, { a: 'c', b: 1 }), false)
     assert.deepStrictEqual(eq.equals({ a: 'a', b: 1 }, { a: 'a', b: 2 }), false)
@@ -57,7 +57,7 @@ describe('Eq', () => {
     }
 
     const eq: Eq<A> = E.Schemable.lazy('A', () =>
-      E.type({
+      E.struct({
         a: E.number,
         b: E.array(eq)
       })
@@ -71,8 +71,8 @@ describe('Eq', () => {
   it('sum', () => {
     const sum = E.sum('_tag')
     const eq = sum({
-      A: E.type({ _tag: E.Schemable.literal('A'), a: E.string }),
-      B: E.type({ _tag: E.Schemable.literal('B'), b: E.number })
+      A: E.struct({ _tag: E.Schemable.literal('A'), a: E.string }),
+      B: E.struct({ _tag: E.Schemable.literal('B'), b: E.number })
     })
     assert.strictEqual(eq.equals({ _tag: 'A', a: 'a' }, { _tag: 'A', a: 'a' }), true)
     assert.strictEqual(eq.equals({ _tag: 'B', b: 1 }, { _tag: 'B', b: 1 }), true)
diff --git a/test/JsonSchema.test.ts b/test/JsonSchema.test.ts
index c8a86d81b..670f4b924 100644
--- a/test/JsonSchema.test.ts
+++ b/test/JsonSchema.test.ts
@@ -1,8 +1,8 @@
 import * as assert from 'assert'
 import Ajv from 'ajv'
 import * as J from './JsonSchema'
-import * as C from 'fp-ts/Const'
-import { pipe } from 'fp-ts/function'
+import * as C from 'fp-ts/lib/Const'
+import { pipe } from 'fp-ts/lib/pipeable'
 
 const ajv = new Ajv()
 
diff --git a/test/JsonSchema.ts b/test/JsonSchema.ts
index bdc331c54..99be4dc9f 100644
--- a/test/JsonSchema.ts
+++ b/test/JsonSchema.ts
@@ -1,6 +1,7 @@
-import * as C from 'fp-ts/Const'
-import { identity, pipe } from 'fp-ts/function'
-import * as R from 'fp-ts/ReadonlyRecord'
+import * as C from 'fp-ts/lib/Const'
+import { identity } from 'fp-ts/lib/function'
+import { pipe } from 'fp-ts/lib/pipeable'
+import * as R from 'fp-ts/lib/ReadonlyRecord'
 import { JSONSchema7 } from 'json-schema'
 import * as S from '../src/Schemable'