What is the ruling on missing the 'Isha prayer until Fajr time, and how can it be made up?

The 'Isha prayer must be performed within its prescribed time, and it is not permissible to delay it until the time of the Fajr prayer, based on Allah’s Almighty saying: ﴿Indeed, prayer has been decreed upon the believers a time-bound ordinance.﴾ and the Prophet’s (peace and blessings be upon him) saying: “Perform the prayer at its appointed time.” Delaying it is considered akin to abandoning it entirely. Moreover, performing prayers in congregation is obligatory according to the soundest opinions of scholars, and whoever does not pray in congregation is sinful unless there is a valid excuse. A missed prayer must be made up immediately, accompanied by seeking forgiveness, remorse, and a firm resolve not to repeat such an act. The Prophet (peace and blessings be upon him) said: “The heaviest prayers for the hypocrites are the ‘Isha prayer and the Fajr prayer. If they knew what rewards they hold, they would come to them, even if they had to crawl.”