If you are also experiencing the following, you should also contact support:
The new update did not change anything software-wise in that regard, so its likely that you suffer a hardware failure, which just by chance started to happen at the same time you updated.
exactly the same here :
No connection through MTP
The Fairphone doesn’t even show up in the device manager of your PC.
It worked untill yesterday before updating and with same cable another device works properly
Cave: It could also be related to driver issues, e.g., on Windows. I noticed that I had trouble on a notebook lately when connecting first in one mode and then choosing another while Win7 was still installing a driver. Neither reboots of the phone nor the Win7 machine could solve this, the phone was invisible afterwards. I haven’t had the time to check that lately, but I will see if this persists. (Promised, but I can’t specify the date and time. ;))
Hi @Johannes_Rohr could you try to restart in recovery mode and try to connect the phone?
In recovery mode there shouldn’t be any app that can interfere with the USB mode, maybe this could assure the problem is hardware related.
Bye! 
@DjDas, I’m not sure what apps you have in mind. USB debugging should work regardless, and also the Linux kernel reporting the presence of a USB device also shouldn’t be impacted by any apps. However, I can report that I have solved the issue for now: I have spent a few bucks on a better quality micro USB cable and that has done the trick. My lesson: Many of the cheap cables on offer are really, really crap, and it definitely makes sense to spend a bit more money on decent hardware…
@Johannes_Rohr I meant also system apps like the settings one which lets you configure the type of device seen by the PC it was a tentative to isolate the problem but it seems it was simpler due to a faulty cable
Glad to read you solved it
Bye!