diff --git a/README.md b/README.md
index e733f37..b528b24 100644
--- a/README.md
+++ b/README.md
@@ -5,9 +5,21 @@
 We want to make an alarm system.
 The system must be able to control locks, react to motion sensors, sound an alarm, flash a LED and be unlocked with a key card and a simple web interface for locking and unlocking.
 
-## Løsningmodel
+## Challenges
 
-## Udfordringer
+### TLS encryption
+
+We tried implementing TLS encryption on the MQTT connection.
+It worked great between the MQTT broker and the controller, but the ESP's had some difficulty validating the brokers certificate.
+This was probably caused because of the MQTT library we used, which doesn't natively support TLS, but relies on the platforms implementation of TLS, which didn't work great together.
+
+If more effort and a bigger willingness to rewrite big parts of the device code it could be achieved.
+But we didn't prioritize it, because it isn't necessary for a working prototype.
+
+### Network
+
+Of course we had problems with the network. As the schools network was very unreliable, or even nonexisting at times.
+This was mostly just a point of frustration, but didn't really cause any real challenges as we solved it by running our own hotspots.
 
 ## Devices