diff --git a/@types/index.d.ts b/@types/index.d.ts
index 274ca03a837fbbf88f6be7d59dfdd4b67c2c1bca..18c8fdcff33b743f2bbd14f7c239a34a4a95a19d 100644
--- a/@types/index.d.ts
+++ b/@types/index.d.ts
@@ -11,12 +11,13 @@ import {
 	fileFromSync
 } from 'fetch-blob/from.js';
 
-type AbortSignal = {
-	readonly aborted: boolean;
+// Avoid type conflicts!
+// type AbortSignal = {
+// 	readonly aborted: boolean;
 
-	addEventListener: (type: 'abort', listener: (this: AbortSignal) => void) => void;
-	removeEventListener: (type: 'abort', listener: (this: AbortSignal) => void) => void;
-};
+// 	addEventListener: (type: 'abort', listener: (this: AbortSignal) => void) => void;
+// 	removeEventListener: (type: 'abort', listener: (this: AbortSignal) => void) => void;
+// };
 
 export type HeadersInit = Headers | Record<string, string> | Iterable<readonly [string, string]> | Iterable<Iterable<string>>;
 
@@ -132,7 +133,7 @@ declare class BodyMixin {
 	readonly size: number;
 
 	/** @deprecated Use `body.arrayBuffer()` instead. */
-	buffer(): Promise<Buffer>;
+	buffer(): Promise<Buffer<ArrayBuffer>>;
 	arrayBuffer(): Promise<ArrayBuffer>;
 	formData(): Promise<FormData>;
 	blob(): Promise<Blob>;
diff --git a/src/index.js b/src/index.js
index 7c4aee87b68f7b3613ce7dad4a570c17ec3630b9..ec69705929ec21da2e1bd28a24f45e45a8b8f5f7 100644
--- a/src/index.js
+++ b/src/index.js
@@ -194,7 +194,8 @@ export default async function fetch(url, options_) {
 							signal: request.signal,
 							size: request.size,
 							referrer: request.referrer,
-							referrerPolicy: request.referrerPolicy
+							referrerPolicy: request.referrerPolicy,
+							ca: request.ca,
 						};
 
 						// when forwarding sensitive headers like "Authorization",
diff --git a/src/request.js b/src/request.js
index af2ebc8e9b6f11783435d3c951eaef500fabbfdc..f45149a76f2940f6a4e1fd2b768a5bdb468de3e6 100644
--- a/src/request.js
+++ b/src/request.js
@@ -141,6 +141,9 @@ export default class Request extends Body {
 		// §5.4, Request constructor steps, step 16.
 		// Default is empty string per https://fetch.spec.whatwg.org/#concept-request-referrer-policy
 		this.referrerPolicy = init.referrerPolicy || input.referrerPolicy || '';
+
+		// Custom Signal Desktop option
+		this.ca = init.ca || input.ca;
 	}
 
 	/** @returns {string} */
@@ -302,7 +305,8 @@ export const getNodeRequestOptions = request => {
 		method: request.method,
 		headers: headers[Symbol.for('nodejs.util.inspect.custom')](),
 		insecureHTTPParser: request.insecureHTTPParser,
-		agent
+		agent,
+		ca: request.ca,
 	};
 
 	return {
diff --git a/src/utils/is.js b/src/utils/is.js
index f9e467e45fe7f214725f49f2bed3f137ddc06e20..c38567519697f8165586754657aaeda0b432e519 100644
--- a/src/utils/is.js
+++ b/src/utils/is.js
@@ -57,6 +57,10 @@ export const isAbortSignal = object => {
 	);
 };
 
+function isSignalVoipUrl(hostname) {
+	return hostname.endsWith('.voip.signal.org');
+}
+
 /**
  * isDomainOrSubdomain reports whether sub is a subdomain (or exact match) of
  * the parent domain.
@@ -69,7 +73,11 @@ export const isDomainOrSubdomain = (destination, original) => {
 	const orig = new URL(original).hostname;
 	const dest = new URL(destination).hostname;
 
-	return orig === dest || orig.endsWith(`.${dest}`);
+	return (
+		orig === dest || orig.endsWith(`.${dest}`) ||
+		// An additional check to keep Authorization for Signal's voip URLs.
+		(isSignalVoipUrl(orig) && isSignalVoipUrl(dest))
+	);
 };
 
 /**