diff --git a/CHANGELOG.md b/CHANGELOG.md
index 355b79907..d7d04d720 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@
 Changes:
 
 - Optimize `u8aToHex` with direct (non-hex) conversion
+- Change all occurences of `.substr(...)` to `.substring(...)`
 
 
 ## 9.1.1 Apr 30, 2022
diff --git a/packages/util-crypto/src/base32/helpers.ts b/packages/util-crypto/src/base32/helpers.ts
index f80076c9d..7e26ad799 100644
--- a/packages/util-crypto/src/base32/helpers.ts
+++ b/packages/util-crypto/src/base32/helpers.ts
@@ -33,7 +33,7 @@ export function createDecode ({ coder, ipfs }: Config, validate: ValidateFn): De
 
     return coder.decode(
       ipfs && ipfsCompat
-        ? value.substr(1)
+        ? value.substring(1)
         : value
     );
   };
diff --git a/packages/util-crypto/src/key/DeriveJunction.ts b/packages/util-crypto/src/key/DeriveJunction.ts
index a7aeee9c9..e705b1e20 100644
--- a/packages/util-crypto/src/key/DeriveJunction.ts
+++ b/packages/util-crypto/src/key/DeriveJunction.ts
@@ -20,7 +20,7 @@ export class DeriveJunction {
   public static from (value: string): DeriveJunction {
     const result = new DeriveJunction();
     const [code, isHard] = value.startsWith('/')
-      ? [value.substr(1), true]
+      ? [value.substring(1), true]
       : [value, false];
 
     result.soft(
diff --git a/packages/util-crypto/src/key/extractPath.ts b/packages/util-crypto/src/key/extractPath.ts
index 54d869f58..c64d21277 100644
--- a/packages/util-crypto/src/key/extractPath.ts
+++ b/packages/util-crypto/src/key/extractPath.ts
@@ -24,7 +24,7 @@ export function keyExtractPath (derivePath: string): ExtractResult {
     constructed = parts.join('');
 
     for (const p of parts) {
-      path.push(DeriveJunction.from(p.substr(1)));
+      path.push(DeriveJunction.from(p.substring(1)));
     }
   }
 
diff --git a/packages/util-crypto/src/mnemonic/toMiniSecret.spec.ts b/packages/util-crypto/src/mnemonic/toMiniSecret.spec.ts
index 590801ead..5dd3effb0 100644
--- a/packages/util-crypto/src/mnemonic/toMiniSecret.spec.ts
+++ b/packages/util-crypto/src/mnemonic/toMiniSecret.spec.ts
@@ -43,7 +43,7 @@ describe('mnemonicToMiniSecret', (): void => {
           u8aToHex(mnemonicToMiniSecret(mnemonic, 'Substrate', onlyJs))
         ).toEqual(
           // mini returned here, only check first 32-bytes (64 hex + 2 prefix)
-          seed.substr(0, 66)
+          seed.substring(0, 66)
         );
       });
     });
diff --git a/packages/util/src/format/formatDecimal.ts b/packages/util/src/format/formatDecimal.ts
index 98dc127c2..09d1c0481 100644
--- a/packages/util/src/format/formatDecimal.ts
+++ b/packages/util/src/format/formatDecimal.ts
@@ -9,7 +9,7 @@ export function formatDecimal (value: string): string {
   // we rather strip and re-add the negative sign in the output
   const isNegative = value[0].startsWith('-');
   const matched = isNegative
-    ? value.substr(1).match(NUMBER_REGEX)
+    ? value.substring(1).match(NUMBER_REGEX)
     : value.match(NUMBER_REGEX);
 
   return matched
diff --git a/packages/util/src/hex/stripPrefix.ts b/packages/util/src/hex/stripPrefix.ts
index 821b0f033..3f14ab591 100644
--- a/packages/util/src/hex/stripPrefix.ts
+++ b/packages/util/src/hex/stripPrefix.ts
@@ -21,7 +21,7 @@ export function hexStripPrefix (value?: string | null): string {
   if (!value || value === '0x') {
     return '';
   } else if (REGEX_HEX_PREFIXED.test(value)) {
-    return value.substr(2);
+    return value.substring(2);
   } else if (REGEX_HEX_NOPREFIX.test(value)) {
     return value;
   }
diff --git a/packages/util/src/hex/toU8a.ts b/packages/util/src/hex/toU8a.ts
index fe1be1b98..afa227652 100644
--- a/packages/util/src/hex/toU8a.ts
+++ b/packages/util/src/hex/toU8a.ts
@@ -42,11 +42,13 @@ export function hexToU8a (_value?: HexString | string | null, bitLength = -1): U
   const length = endLength - offset - mod;
 
   for (let i = 0; i < length; i += 2) {
-    dv.setUint16(i, HEX_TO_U16[value.substr(i * 2, 4)]);
+    const idx = i * 2;
+
+    dv.setUint16(i, HEX_TO_U16[value.substring(idx, idx + 4)]);
   }
 
   if (mod) {
-    dv.setUint8(length, HEX_TO_U8[value.substr(value.length - 2, 2)]);
+    dv.setUint8(length, HEX_TO_U8[value.substring(value.length - 2)]);
   }
 
   return result;
diff --git a/packages/util/src/logger.ts b/packages/util/src/logger.ts
index a086bed0d..d097dbfd8 100644
--- a/packages/util/src/logger.ts
+++ b/packages/util/src/logger.ts
@@ -59,7 +59,7 @@ function formatWithLength (maxLength: number): (v: unknown) => unknown {
 
     return r.length < maxLength
       ? v
-      : `${r.substr(0, maxLength)} ...`;
+      : `${r.substring(0, maxLength)} ...`;
   };
 }
 
diff --git a/packages/util/src/string/shorten.ts b/packages/util/src/string/shorten.ts
index bc676b2a9..a8e649b4d 100644
--- a/packages/util/src/string/shorten.ts
+++ b/packages/util/src/string/shorten.ts
@@ -20,5 +20,5 @@ import type { AnyString } from '../types';
 export function stringShorten (value: AnyString, prefixLength = 6): string {
   return value.length <= 2 + 2 * prefixLength
     ? value.toString()
-    : `${value.substr(0, prefixLength)}…${value.slice(-prefixLength)}`;
+    : `${value.substring(0, prefixLength)}…${value.slice(-prefixLength)}`;
 }