Bug 515566

Summary:	v1.35.1 breaks connectivity
Product:	[Applications] kdeconnect	Reporter:	Manolis Tzanidakis <mtzanidakis>
Component:	android-application	Assignee:	Albert Vaca Cintora <albertvaka>
Status:	CONFIRMED ---
Severity:	normal	CC:	andrew.g.r.holmes, Linus, nicolas.fella
Priority:	NOR
Version First Reported In:	unspecified
Target Milestone:	---
Platform:	Android
OS:	Android 14.x
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Manolis Tzanidakis 2026-02-05 18:06:12 UTC

SUMMARY

I'm using KDEConnect to connect my Pixel 6 (Android 16) and my laptop (NixOS unstable, KDE Plasma 6.5.5) via tailscale, by manually adding the laptop's hostname.
After update the android app to 1.35.1 the connectivity broke. I downgraded to 1.34.1 (from APKmirror) and it works again.

STEPS TO REPRODUCE
1. Upgrade android app to v1.35.1

OBSERVED RESULT

Can not connect to my laptop via tailscale.

EXPECTED RESULT

Should connect.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: 6.18.8
KDE Plasma Version: 6.5.5
KDE Frameworks Version: 6.22.0 
Qt Version: 6.10.1

ADDITIONAL INFORMATION
Same setup was working the last 2 years at least, broke on v1.35.1.

Comment 1 Linus Dierheimer 2026-02-07 11:56:26 UTC

I have the same problem. Downgrading to 1.34 fixed the issue. My phone is a Samsung Galaxy S9 with Android 10.

While trying to connect, i can see the following two lines in the log from kdeconnectd on my computer, each time i refresh on the phone:
kdeconnect.core: TCP connection done (i'm the existing device)
kdeconnect.core: Starting server ssl (I'm the client TCP socket)
(Nothing more)

Hope this helps. Happy to provide more infos / logs upon request.

Comment 2 Linus Dierheimer 2026-02-07 12:09:22 UTC

Some more infos i forgot to mention:
- I don't use tailscale or similar. Both devices are on the same network, same VLAN.
- When it stopped working, i thought repairing might solve it. However they didn't even find each other, neither per udp broadcast, MDNS or explicit IPv4 and IPv6 (technically they did, because i could see the initial handshake in the logs of kdeconnectd and avahi browse, but not according to the UI)
- Path MTU is fine (ping -M do -s 1472 <IP> works). This broke TLS for me before, so i checked that.
- I tried  "curl <IP>:1716". On the working version, i get a connection reset from my phone. On the broken version there simply is no response.

Comment 3 Linus Dierheimer 2026-02-09 16:58:25 UTC

I found this commit: https://bugs.kde.org/show_bug.cgi?id=515707.

My Dormitory uses 100.122.0.0/16 as its subnet. That might be the culprit