diff --git a/cfg/tsconfig.json b/cfg/tsconfig.json
index c8e1663..682204f 100644
--- a/cfg/tsconfig.json
+++ b/cfg/tsconfig.json
@@ -10,7 +10,7 @@
     "outDir": "${configDir}/dist",
 
     // Target/module
-    "target": "es2023",
+    "target": "es2022", // todo: es2023 when all consumers are on ts5.6+
     "lib": ["esnext"], // add "dom" if needed
     // module `nodenext` is a modern mode that auto-detects cjs/esm
     // it also defaults `esModuleInterop` and `allowSyntheticDefaultImports` to true
diff --git a/src/testing/time.util.test.ts b/src/testing/time.util.test.ts
index 9e9d1df..4df2889 100644
--- a/src/testing/time.util.test.ts
+++ b/src/testing/time.util.test.ts
@@ -1,4 +1,4 @@
-import { MOCK_TS_2018_06_21, mockTime, mockTimeMillis, resetTime } from './time.util'
+import { MOCK_TS_2018_06_21, mockTime, resetTime } from './time.util'
 
 const now = Date.now()
 
@@ -15,10 +15,6 @@ test('mockTime default', () => {
 
   expect(Date.now()).toBeGreaterThanOrEqual(now)
 
-  mockTimeMillis(123_456)
-
-  expect(Date.now()).toBe(123_456)
-
   resetTime()
 
   expect(new Date().getFullYear()).toBeGreaterThan(2018)
diff --git a/src/testing/time.util.ts b/src/testing/time.util.ts
index fb35cc3..1b2ec0b 100644
--- a/src/testing/time.util.ts
+++ b/src/testing/time.util.ts
@@ -1,17 +1,14 @@
+import type { UnixTimestamp } from '@naturalcycles/js-lib'
 import timekeeper from 'timekeeper'
 
-export const MOCK_TS_2018_06_21 = 1_529_539_200
+export const MOCK_TS_2018_06_21 = 1_529_539_200 as UnixTimestamp
 
 /**
  * Locks time-related functions to return always same time.
  * For deterministic tests.
  */
 export function mockTime(ts = MOCK_TS_2018_06_21): void {
-  mockTimeMillis(ts * 1000)
-}
-
-export function mockTimeMillis(millis = MOCK_TS_2018_06_21 * 1000): void {
-  timekeeper.freeze(millis)
+  timekeeper.freeze(ts * 1000)
 }
 
 export function resetTime(): void {
diff --git a/yarn.lock b/yarn.lock
index d532079..cfa76a1 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1014,17 +1014,17 @@
     typescript "^5.0.2"
 
 "@naturalcycles/js-lib@^14.0.0", "@naturalcycles/js-lib@^14.244.0":
-  version "14.260.0"
-  resolved "https://registry.yarnpkg.com/@naturalcycles/js-lib/-/js-lib-14.260.0.tgz#1086a684ff4ccd028be053d9fa701d9cd5358dbf"
-  integrity sha512-GfkmD+xAP8GODx2kh++5MErmDMu50S/QAslbtoaKtpWrmFlfaMEtNpYLXLDYGjcj4NJRilbE9hwiM8Rizs5V2g==
+  version "14.261.0"
+  resolved "https://registry.yarnpkg.com/@naturalcycles/js-lib/-/js-lib-14.261.0.tgz#e85aaa6c68b5efeada4e4cfdcb5c00e5e30a8d3a"
+  integrity sha512-7+jI98zjNcifAkQu8q4UHhXzeclJVIDfoE8GHpwdqjbaT6a9p2KOikvBjMd1SdCH1OTR6ijBPNvax1VS9Jb2qw==
   dependencies:
     tslib "^2.0.0"
     zod "^3.20.2"
 
 "@naturalcycles/nodejs-lib@^13.0.1":
-  version "13.36.0"
-  resolved "https://registry.yarnpkg.com/@naturalcycles/nodejs-lib/-/nodejs-lib-13.36.0.tgz#cea71bd4e88ba37d28cb4af9a12fd5e0678d4fd0"
-  integrity sha512-v6t2P2HGFhaCFN9iM5Fgvg7qnf7FAK76SatCLGoQtdozyUX7xnPj8xUe35ft2YGvmu1TaWU4UWqRKTJEWGwByA==
+  version "13.37.1"
+  resolved "https://registry.yarnpkg.com/@naturalcycles/nodejs-lib/-/nodejs-lib-13.37.1.tgz#c30ace789bf7a484c548bb7d67fd6501dcb6272e"
+  integrity sha512-Ltw5SAGUkLH4pp+juov16LOwjSCyXdFBEgLXcCbOcQV9a5l9jLZouULrSQ+CpBvpXTElKRAFqWobU57wQHVtgw==
   dependencies:
     "@naturalcycles/js-lib" "^14.244.0"
     "@types/js-yaml" "^4.0.9"