Downgrade Firmware Downgrade Firmware powercom (Programmer) (OP) 17 Apr 21 13:46 Hello ,how can downgrade firmware KX-NS500 . Thank you guys . RE: Downgrade Firmware Mike_K (TechnicalUser) 18 Apr 21 12:39 Dealers, who repiads PBXs, has a spesial software for it. After repiering NS500 has a firmware ver. 1.010.062. I am wondering, why need downgrade firmware KX-NS500? RE: Downgrade Firmware powercom (Programmer) (OP) 19 Apr 21 19:14 i need to downgrade from version PFMPR_008_000_550 to version PFMPR_007_001_430 RE: Downgrade Firmware Ired1980 (TechnicalUser) 23 Apr 21 06:26 Try to ask any dealer, who repairs PBXs, to downgrade firmare at ver. 1.010. After that you can upgrade you PBX at the version you need. But what for do you need it? ------------ Telephone communication like an air: you do not notice it until you spoil it.