diff --git a/package.json b/package.json
index 189af6b72..eddca22a0 100644
--- a/package.json
+++ b/package.json
@@ -7,7 +7,7 @@
     "packages/*"
   ],
   "resolutions": {
-    "typescript": "^4.2.3"
+    "typescript": "^4.2.4"
   },
   "scripts": {
     "build": "polkadot-dev-build-ts",
diff --git a/packages/networks/src/index.spec.ts b/packages/networks/src/index.spec.ts
index faa568b8b..5a6b47fba 100644
--- a/packages/networks/src/index.spec.ts
+++ b/packages/networks/src/index.spec.ts
@@ -1,7 +1,9 @@
 // Copyright 2017-2021 @polkadot/networks authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import filtered, { available } from '.';
+import type { NetworkFromSubstrate } from './types';
+
+import filtered, { all, available } from '.';
 
 describe('filtered', (): void => {
   it('has the correct starting order', (): void => {
@@ -11,4 +13,19 @@ describe('filtered', (): void => {
   it('has no ignored networks', (): void => {
     expect(available.some(({ isIgnored }) => isIgnored)).toEqual(false);
   });
+
+  it('has no ss58 duplicates', (): void => {
+    const dupes: NetworkFromSubstrate[] = [];
+    const uniques: NetworkFromSubstrate[] = [];
+
+    all.forEach((a): void => {
+      if (uniques.some((u) => u.prefix === a.prefix)) {
+        dupes.push(a);
+      } else {
+        uniques.push(a);
+      }
+    });
+
+    expect(dupes).toEqual([]);
+  });
 });
diff --git a/packages/x-fetch/package.json b/packages/x-fetch/package.json
index 2f5ffef03..d69ab92a3 100644
--- a/packages/x-fetch/package.json
+++ b/packages/x-fetch/package.json
@@ -17,7 +17,7 @@
   "dependencies": {
     "@babel/runtime": "^7.13.10",
     "@polkadot/x-global": "6.0.6-3",
-    "@types/node-fetch": "^2.5.8",
+    "@types/node-fetch": "^2.5.10",
     "node-fetch": "^2.6.1"
   }
 }
diff --git a/packages/x-global/package.json b/packages/x-global/package.json
index 0705ed079..a8bf22359 100644
--- a/packages/x-global/package.json
+++ b/packages/x-global/package.json
@@ -14,7 +14,7 @@
   "homepage": "https://github.com/polkadot-js/common/tree/master/packages/x-global#readme",
   "dependencies": {
     "@babel/runtime": "^7.13.10",
-    "@types/node-fetch": "^2.5.8",
+    "@types/node-fetch": "^2.5.10",
     "node-fetch": "^2.6.1"
   }
 }
diff --git a/yarn.lock b/yarn.lock
index db46a0326..f1e931db6 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -2088,7 +2088,7 @@ __metadata:
   dependencies:
     "@babel/runtime": ^7.13.10
     "@polkadot/x-global": 6.0.6-3
-    "@types/node-fetch": ^2.5.8
+    "@types/node-fetch": ^2.5.10
     node-fetch: ^2.6.1
   languageName: unknown
   linkType: soft
@@ -2098,7 +2098,7 @@ __metadata:
   resolution: "@polkadot/x-global@workspace:packages/x-global"
   dependencies:
     "@babel/runtime": ^7.13.10
-    "@types/node-fetch": ^2.5.8
+    "@types/node-fetch": ^2.5.10
     node-fetch: ^2.6.1
   languageName: unknown
   linkType: soft
@@ -2390,13 +2390,13 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@types/node-fetch@npm:^2.5.8":
-  version: 2.5.8
-  resolution: "@types/node-fetch@npm:2.5.8"
+"@types/node-fetch@npm:^2.5.10":
+  version: 2.5.10
+  resolution: "@types/node-fetch@npm:2.5.10"
   dependencies:
     "@types/node": "*"
     form-data: ^3.0.0
-  checksum: 608cdd6aed2c6a44a26406eb63475d4bfb8f63f78f22f747e30dd7cda309b86dc019e4427b9092011541da95d83ef03e2e6558c37d39221c0931617f32d3c4e1
+  checksum: 7687038f73cf0f2e4bac8ced3abdfbb77f8b2719de2f180d0064238d7460c8b4dc0b39c08da35a76d7db9f86528599ea0f7cee7c468ad7cfecfe2db1c5863641
   languageName: node
   linkType: hard
 
@@ -10689,23 +10689,23 @@ fsevents@~2.1.2:
   languageName: node
   linkType: hard
 
-"typescript@npm:^4.2.3":
-  version: 4.2.3
-  resolution: "typescript@npm:4.2.3"
+"typescript@npm:^4.2.4":
+  version: 4.2.4
+  resolution: "typescript@npm:4.2.4"
   bin:
     tsc: bin/tsc
     tsserver: bin/tsserver
-  checksum: 06e8470f317db6f5e2fce809b20eb84a67a7d8179057abff36e5427bd1b891bd08e54581ff81f0fa36aef9b6d1eb0f54eaf6e2643c6dbd4e37a0adcc41eed256
+  checksum: edaede2fa77f56b7fba80ee624a2368ab1216e75b0434d968ccb47ab0a5e2f6d94f848b3b111c1237dd71e988cd376af26370dcdad3b94355c76e759f0dd0a1e
   languageName: node
   linkType: hard
 
-"typescript@patch:typescript@npm%3A^4.2.3#builtin<compat/typescript>":
-  version: 4.2.3
-  resolution: "typescript@patch:typescript@npm%3A4.2.3#builtin<compat/typescript>::version=4.2.3&hash=a45b0e"
+"typescript@patch:typescript@npm%3A^4.2.4#builtin<compat/typescript>":
+  version: 4.2.4
+  resolution: "typescript@patch:typescript@npm%3A4.2.4#builtin<compat/typescript>::version=4.2.4&hash=a45b0e"
   bin:
     tsc: bin/tsc
     tsserver: bin/tsserver
-  checksum: a8956044aabf730699bcc3c2475efdd3f35e509329325cf60b4989761d4c2188e2c474183e2cf92b8c201fcf976814a5a16f144508b2a832643c4f972d0ab803
+  checksum: 3be44317593182e8ce494c114e7ad9b0bb2553a22f3085cc6da4f0a36912c20850daa9be4c898af2ab6fc8b12f430c1c9e46ac715721867cd38643f2350d3ef9
   languageName: node
   linkType: hard