diff --git a/src/formats.ts b/src/formats.ts
index 46f1192..3ab44f8 100644
--- a/src/formats.ts
+++ b/src/formats.ts
@@ -62,7 +62,7 @@ export const fullFormats: DefinedFormats = {
   hostname:
     /^(?=.{1,253}\.?$)[a-z0-9](?:[a-z0-9-]{0,61}[a-z0-9])?(?:\.[a-z0-9](?:[-0-9a-z]{0,61}[0-9a-z])?)*\.?$/i,
   // optimized https://www.safaribooksonline.com/library/view/regular-expressions-cookbook/9780596802837/ch07s16.html
-  ipv4: /^(?:(?:25[0-5]|2[0-4]\d|[01]?\d\d?)\.){3}(?:25[0-5]|2[0-4]\d|[01]?\d\d?)$/,
+  ipv4: /^(?:(?:25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)\.){3}(?:25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)$/,
   ipv6: /^((([0-9a-f]{1,4}:){7}([0-9a-f]{1,4}|:))|(([0-9a-f]{1,4}:){6}(:[0-9a-f]{1,4}|((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3})|:))|(([0-9a-f]{1,4}:){5}(((:[0-9a-f]{1,4}){1,2})|:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3})|:))|(([0-9a-f]{1,4}:){4}(((:[0-9a-f]{1,4}){1,3})|((:[0-9a-f]{1,4})?:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(([0-9a-f]{1,4}:){3}(((:[0-9a-f]{1,4}){1,4})|((:[0-9a-f]{1,4}){0,2}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(([0-9a-f]{1,4}:){2}(((:[0-9a-f]{1,4}){1,5})|((:[0-9a-f]{1,4}){0,3}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(([0-9a-f]{1,4}:){1}(((:[0-9a-f]{1,4}){1,6})|((:[0-9a-f]{1,4}){0,4}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(:(((:[0-9a-f]{1,4}){1,7})|((:[0-9a-f]{1,4}){0,5}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:)))$/i,
   regex,
   // uuid: http://tools.ietf.org/html/rfc4122
@@ -149,7 +149,7 @@ function compareDate(d1: string, d2: string): number | undefined {
   return 0
 }
 
-const TIME = /^(\d\d):(\d\d):(\d\d(?:\.\d+)?)(z|([+-]\d\d)(?::?(\d\d))?)?$/i
+const TIME = /^(\d\d):(\d\d):(\d\d(?:\.\d+)?)(z|([+-])(\d\d)(?::?(\d\d))?)?$/i
 
 function time(str: string, withTimeZone?: boolean, strictTime?: boolean): boolean {
   const matches: string[] | null = TIME.exec(str)
@@ -158,14 +158,15 @@ function time(str: string, withTimeZone?: boolean, strictTime?: boolean): boolea
   const min: number = +matches[2]
   const sec: number = +matches[3]
   const tz: string | undefined = matches[4]
-  const tzH: number = +(matches[5] || 0)
-  const tzM: number = +(matches[6] || 0)
-  return (
-    ((hr <= 23 && min <= 59 && sec < 60 && tzH <= 24 && tzM < 60) ||
-      // leap second
-      (hr - tzH === 23 && min - tzM === 59 && sec < 61 && tzH <= 24 && tzM < 60)) &&
-    (!withTimeZone || (tz !== "" && (!strictTime || !!tz)))
-  )
+  const tzSign: number = matches[5] === "-" ? -1 : 1
+  const tzH: number = +(matches[6] || 0)
+  const tzM: number = +(matches[7] || 0)
+  if (tzH > 23 || tzM > 59 || (withTimeZone && (tz === "" || (strictTime && !tz)))) return false
+  if (hr <= 23 && min <= 59 && sec < 60) return true
+  // leap second
+  const utcMin = min - tzM * tzSign
+  const utcHr = hr - tzH * tzSign - (utcMin < 0 ? 1 : 0)
+  return (utcHr === 23 || utcHr === -1) && (utcMin === 59 || utcMin === -1) && sec < 61
 }
 
 function strict_time(str: string): boolean {
diff --git a/tests/JSON-Schema-Test-Suite b/tests/JSON-Schema-Test-Suite
index 21555a8..e82bfdf 160000
--- a/tests/JSON-Schema-Test-Suite
+++ b/tests/JSON-Schema-Test-Suite
@@ -1 +1 @@
-Subproject commit 21555a8540584447a9f8ea659accd0ce79bd36e5
+Subproject commit e82bfdfa59c63cc74175d35fac81bb95e61db24b
diff --git a/tests/json-schema.spec.js b/tests/json-schema.spec.js
index 74af2ee..1cc4c5c 100644
--- a/tests/json-schema.spec.js
+++ b/tests/json-schema.spec.js
@@ -2,30 +2,47 @@ const jsonSchemaTest = require("json-schema-test")
 const Ajv = require("ajv").default
 const addFormats = require("../dist")
 
-const ajv = new Ajv({$data: true, strictTypes: false, formats: {allowedUnknown: true}})
-addFormats(ajv)
-
-jsonSchemaTest(ajv, {
-  description: `JSON-Schema Test Suite draft-07 formats + extras`,
+jsonSchemaTest(getAjv(true), {
+  description: `JSON-Schema Test Suite formats`,
   suites: {
     "draft-07 formats": "./JSON-Schema-Test-Suite/tests/draft7/optional/format/*.json",
     "draft-07 regex": "./JSON-Schema-Test-Suite/tests/draft7/optional/ecmascript-regex.json",
     "draft-2019-09 formats": "./JSON-Schema-Test-Suite/tests/draft2019-09/optional/format/*.json",
     "draft-2019-09 regex":
       "./JSON-Schema-Test-Suite/tests/draft2019-09/optional/ecmascript-regex.json",
-    extras: "./extras/{**/,}*.json",
+    "draft-2020-12 formats": "./JSON-Schema-Test-Suite/tests/draft2020-12/optional/format/*.json",
+    "draft-2020-12 regex":
+      "./JSON-Schema-Test-Suite/tests/draft2020-12/optional/ecmascript-regex.json",
   },
   only: [],
   skip: ["format/idn-email", "format/idn-hostname", "format/iri", "format/iri-reference"],
-  afterEach({valid, errors}) {
-    expect(typeof valid).toBe("boolean")
-    if (valid === true) {
-      expect(errors).toBe(null)
-    } else {
-      expect(Array.isArray(errors)).toBe(true)
-      errors.every((err) => expect(typeof err).toBe("object"))
-    }
-  },
+  afterEach,
   cwd: __dirname,
   hideFolder: "draft7/",
 })
+
+jsonSchemaTest(getAjv(), {
+  description: `Extra tests`,
+  suites: {
+    extras: "./extras/{**/,}*.json",
+  },
+  only: [],
+  afterEach,
+  cwd: __dirname,
+})
+
+function getAjv(strictTime) {
+  const ajv = new Ajv({$data: true, strictTypes: false, formats: {allowedUnknown: true}})
+  addFormats(ajv, {mode: "full", keywords: true, strictTime})
+  return ajv
+}
+
+function afterEach({valid, errors}) {
+  expect(typeof valid).toBe("boolean")
+  if (valid === true) {
+    expect(errors).toBe(null)
+  } else {
+    expect(Array.isArray(errors)).toBe(true)
+    errors.every((err) => expect(typeof err).toBe("object"))
+  }
+}