Renters (Reform) Bill Webinar question about S8 eviction requirements and timelines

Rent Arrears

Hi, all. 

Just attended a Zoom meeting where it was confirmed that the fixed term tenancy will be abolished. That means that T potentially can use it as short-term let. It's not so clear what the position of a LL is, though. If T moved in and doesn't pay for over 2 months, can LL initiate S8 eviction process? The speaker kept repeating the words "serious and persistent rent arrears". How does it translate into a period of time legally? Is 2 months one day still enough or not anymore? I'd really appreciate a clear answer to this question if anyone can help.