[milankragujevic]

I'm sorry if I said something controversial, I can take a look and send you relevant info, but for now please take a look at:

Telekom Srbija (Serbia)

SBB (Serbia)

Orion telekom (Serbia)

Supernova (Serbia)

A1 Slovenia

Telekom Slovenije (Slovenia)

Telemach (Slovenia)

A1 HR (Croatia)

Telemach (Croatia)

T-Com (Croatia)

Iskon (Croatia)

Telekom Srpske (Bosnia and Herzegovina)

Telemach (Bosnia and Herzegovina)

Triontel (Bosnia and Herzegovina)

Mtel (Montenegro)

T-Com (Montenegro)

T-Com (North Macedonia)

A1 (North Macedonia)

... and similar in Bulgaria

On all relevant websites, you cannot find info on BYO, and I can personally guarantee you cannot use your device on GPON or DOCSIS networks.

Only Romania is an exception.