diff --git a/lib/client.js b/lib/client.js
index 1a325a9..15df4ed 100644
--- a/lib/client.js
+++ b/lib/client.js
@@ -177,7 +177,7 @@ export default class Client extends EventTarget {
 		var l = s.split(" ");
 		l.forEach((s) => {
 			var parts = s.split("=");
-			var k = parts[0];
+			var k = parts[0].toLowerCase();
 			var v = "";
 			if (parts.length > 1) {
 				v = parts[1];
@@ -239,6 +239,7 @@ export default class Client extends EventTarget {
 			break;
 		case "DEL":
 			args[0].split(" ").forEach((cap) => {
+				cap = cap.toLowerCase();
 				delete this.availableCaps[cap];
 				delete this.enabledCaps[cap];
 			});
@@ -247,6 +248,7 @@ export default class Client extends EventTarget {
 		case "ACK":
 			console.log("Server ack'ed caps:", args[0]);
 			args[0].split(" ").forEach((cap) => {
+				cap = cap.toLowerCase();
 				this.enabledCaps[cap] = true;
 
 				if (cap == "sasl" && this.params.saslPlain) {