AP FW 11.0.019 Downgrade package - where ?!

As far as i know, there is no way to do this. Why do you want to downgrade? 

11.0.020 bricked APX 320 or made it unusable ...

APX320 P52003... doesn´t work with FW 11.0.019
APX320 P52007... does work fine 

They are both registered in WLAN, but P52003 stays inactive forever

On an old XG106W with 19.0.1 and FW 11.0.019 P52003... works fine

But i made the mistake to trust the new AP FW 11.0.020 release .. at our XGS2100

And Sophos Support has no solution..

What about Central Wireless? 

I´d like to add the APX to our XGS2100 Firewall ...

I can´t login to central wireless, (tried this, but doesn´t like me).
I think the APX is briked or useless in this old revision and Sophos need to RMA this brick...

Would recommend to migrate to Central Wireless anyway. You can do the same stuff there and can manage the APX without the need more load on your firewall (for no reason). 

You need to setup a Central Account first: https://www.sophos.com/en-us/products/sophos-central/free-trial

The Trial will expire but Central Wireless and Firewall Management will stay.

BTW: You do not manage your firewalls in Central? 

where do i get a logon to Central Wireless.

i can´t register for a trial (i already have an accout) & i can´t reset my passwort.
It always says authentication failed...

Hello juergenb52,

I would suggest flash the APX using Sophos Flash Tool - https://support.sophos.com/support/s/article/KB-000039314?language=en_US
And then register the APX with the free license available on the Sophos central: https://techvids.sophos.com/watch/3sKLp6vWfJPzxWQeT6f9C3

Flash tool works only 

if the APX doesn´t boot or connect to XGS ..

But it connects fine and is seen by firewall:
it works with 18.5.3, 19.0.1 and with AP FW 11.0.020 ..

II can´t get any login to central 
Always authentication failed (even if i reset password)

If you get an Auth Failed, likely you did not have a Central Account created for this MySophos ID Account.

Try to register this Email for Central again. You should get an "Email already in Use". If not, you account was not created. 

i get an "Email already in Use"

But i can´t reset or login.. 
I do get the authentication code from Microsoft ...