diff --git a/ts/test-node/util/ringrtc/normalizeGroupCallTimestamp_test.ts b/ts/test-node/util/ringrtc/normalizeGroupCallTimestamp_test.ts
index 5a549b9404..d4804700f2 100644
--- a/ts/test-node/util/ringrtc/normalizeGroupCallTimestamp_test.ts
+++ b/ts/test-node/util/ringrtc/normalizeGroupCallTimestamp_test.ts
@@ -6,53 +6,13 @@ import { assert } from 'chai';
 import { normalizeGroupCallTimestamp } from '../../../util/ringrtc/normalizeGroupCallTimestamp';
 
 describe('normalizeGroupCallTimestamp', () => {
-  it('returns undefined if passed NaN', () => {
-    assert.isUndefined(normalizeGroupCallTimestamp(NaN));
-  });
-
-  it('returns undefined if passed 0', () => {
-    assert.isUndefined(normalizeGroupCallTimestamp(0));
-    assert.isUndefined(normalizeGroupCallTimestamp(-0));
-  });
-
-  it('returns undefined if passed a negative number', () => {
-    assert.isUndefined(normalizeGroupCallTimestamp(-1));
-    assert.isUndefined(normalizeGroupCallTimestamp(-123));
-  });
-
   it('returns undefined if passed a string that cannot be parsed as a number', () => {
     assert.isUndefined(normalizeGroupCallTimestamp(''));
     assert.isUndefined(normalizeGroupCallTimestamp('uhhh'));
   });
 
-  it('returns undefined if passed a BigInt of 0', () => {
-    assert.isUndefined(normalizeGroupCallTimestamp(BigInt(0)));
-  });
-
-  it('returns undefined if passed a negative BigInt', () => {
-    assert.isUndefined(normalizeGroupCallTimestamp(BigInt(-1)));
-    assert.isUndefined(normalizeGroupCallTimestamp(BigInt(-123)));
-  });
-
-  it('returns undefined if passed a non-parseable type', () => {
-    [
-      undefined,
-      null,
-      {},
-      [],
-      [123],
-      Symbol('123'),
-      { [Symbol.toPrimitive]: () => 123 },
-      // eslint-disable-next-line no-new-wrappers
-      new Number(123),
-    ].forEach(value => {
-      assert.isUndefined(normalizeGroupCallTimestamp(value));
-    });
-  });
-
-  it('returns positive numbers passed in', () => {
-    assert.strictEqual(normalizeGroupCallTimestamp(1), 1);
-    assert.strictEqual(normalizeGroupCallTimestamp(123), 123);
+  it('returns undefined if passed 0', () => {
+    assert.isUndefined(normalizeGroupCallTimestamp('0'));
   });
 
   it('parses strings as numbers', () => {
@@ -66,9 +26,4 @@ describe('normalizeGroupCallTimestamp', () => {
       123456789012345
     );
   });
-
-  it('converts positive BigInts to numbers', () => {
-    assert.strictEqual(normalizeGroupCallTimestamp(BigInt(1)), 1);
-    assert.strictEqual(normalizeGroupCallTimestamp(BigInt(123)), 123);
-  });
 });
diff --git a/ts/util/ringrtc/normalizeGroupCallTimestamp.ts b/ts/util/ringrtc/normalizeGroupCallTimestamp.ts
index 2bf0f44c5c..55b2539e17 100644
--- a/ts/util/ringrtc/normalizeGroupCallTimestamp.ts
+++ b/ts/util/ringrtc/normalizeGroupCallTimestamp.ts
@@ -2,31 +2,12 @@
 // SPDX-License-Identifier: AGPL-3.0-only
 
 /**
- * Normalizes group call timestamps (`addedTime` and `speakerTime`) into numbers. We
- * expect RingRTC to send a string, but it sends a malformed number as of this writing,
- * RingRTC 2.8.3.
- *
- * We could probably safely do `Number(fromRingRtc)` and be done, but this is extra-
- * careful.
+ * Normalizes RingRTC group call timestamps (`addedTime` and `speakerTime`) into numbers.
  */
 export function normalizeGroupCallTimestamp(
-  fromRingRtc: unknown
+  fromRingRtc: string
 ): undefined | number {
-  let asNumber: number;
-
-  switch (typeof fromRingRtc) {
-    case 'number':
-      asNumber = fromRingRtc;
-      break;
-    case 'string':
-      asNumber = parseInt(fromRingRtc.slice(0, 15), 10);
-      break;
-    case 'bigint':
-      asNumber = Number(fromRingRtc);
-      break;
-    default:
-      return undefined;
-  }
+  const asNumber = parseInt(fromRingRtc.slice(0, 15), 10);
 
   if (Number.isNaN(asNumber) || asNumber <= 0) {
     return undefined;