What is the last time for the 'Isha prayer, and is delaying it beyond this time considered makruh tahrima (reprehensible to the point of being unlawful) or makruh tanzihi (reprehensible to the point of being disliked)?

The 'Isha' prayer has two times:

- An optional time: From the disappearance of the red twilight until the first third of the night and before the middle of the night.

- A necessary time: This extends until Fajr (dawn).

It is not permissible to delay the prayer beyond its optional time except for a valid excuse, such as sleep or forgetfulness; otherwise, the one who does so commits a sin.