From the tail of the aircraft it can identified as a MiG-21, see the below images for comparison
Fadi Mqayed highlighted this earlier video of the MiG-21 shot down in Idlib several days ago which shows it having the serial number 2271, while the new video has the number 2280, confirming this is a different aircraft. As of yet there's no reports on which weapon was used to shoot down the aircraft.
Update September 4th A second video has been posted from the crash site
Update September 5th Reuters has more details of the incident, quoting opposition fighters as saying the jet was shot down by 14.5mm anti-aircraft guns, likely a KPV heavy machine gun.
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