During the upcoming RMT strike days on 20 and 22 July the last HEX service will be at 8.40 pm from Paddington, 8.42 pm from Heathrow Terminal 5, and 8.47 pm from Heathrow Central.
And on 24 September due to engineering work the first train from Heathrow will be at 7.30 am.
As far as has been announced currently the Elizabeth Line will operate normally on the Strike days.