QNAP Firmware recall / revoke overview

QNAP communication

QNAP had no luck this year with its firmware releases. Until now, 10 firmwares have been released this year, 6 7 have been vanished from the download center without further notice. This is no good communication towards QNAP customers. Therefore I will try to collect and list the recalled firmwares which I can find out. If I missed something please let me know in the comments. I will try to correct it as soon as possible.
The reasons for a firmware recall are not published by QNAP. I can only guess and do some research on the internet to get an idea which problems are connected to which firmware.

ARM Annapurna Labs

I maintain 4 QNAP devices from the ARM Annapurna Labs series:

2x TS-231P (one of it is provided by QNAP)
1x TS-431+
1x TS-231+

The critics mentioned here do only concern this series. It looks like that the Intel devices are not affected by the technical problems described here.

Recalled firmware overview

2018

month	QTS version	likely cause	source
March	4.3.4.0516	files vanish	QNAP Club
April	4.3.4.0537	files and folders vanish encryption	QNAP Club
May	4.3.4.0569	memory leak	QNAP Forum
May	4.3.4.0588	Logon problems with Firefox	QNAP Club Forum
May	4.3.4.0593	Logon problems still not solved	QNAP Club Forum
August	4.3.4.0675	fan control shutdown not possible bleeper issue (?)	QNAP Club Forum
November	4.3.6.0776	???	QNAP Club Forum

Known issues for released firmware

The firmware which is still online has also serious problems. I will try to keep track of it every time a new release appears on the QNAP website.