The timings for the Dubai Metro for Ramadan have not actually changed at all and are the usual timings as per the following:
So both the red line and the green line have the same operating hours as follows:
Monday to Thursday
5am until midnight
Friday
5am until 1am the next day
Saturday
5am until midnight
Sunday
8am until midnight
The end of Ramadan is announced closer to the time and depending on if Ramadan lasts for 29 or 30 days, the Eid Al Fitr public holiday (which starts immediately after Ramadan) is expected happen from March 18 to March 20.