It might have been a single guy with a Igla for all we know.
You don't need fancy new toys to shoot down a single plane in daylight.
It could even have been "friendly" fire.
I don't think the insurgents are well trained in aircraft recognition so if they have MANPAD they will use them.
Up to now, we still do not know, if plane was actually shot down, or it crashed inside Syrian territory. But anyway Buk-M2, which Syria have, is more than enough to shot down that F-4.
In the 1990s, Almaz-Antey, as all other parts of the soviet military-industrial complex was desperately pitching their stuff to everybody and his dog and they very often announced premature successes. Part inexperience in capitalism (e.g. confusing signature of a MoU with closing of the contract by press department) part deliberate tactic to keep them in the headlines.
These bogus reports and the over-eagerness of american analysts to overestimate the capabilities of everyone except China created a lot of BS reports.
....From your site.Although Damascus would like to receive S-300PMU Favorit (SA-20 Gargoyle) long-range SAMs and Iskander (SS-26 Stone) mobile theater-level missiles, Moscow refuses to supply them because it does not want to upset the regional military balance and to sour relations with Israel and the United States. Additionally, Syrian officials are said to be interested in Russia’s advanced S-400 air- and missile defense system. The Kremlin is also unlikely to agree.
Syria wish to have S-300, but they don't actually have it. Also Buk-M2 is more capable system than early versions of S-300.
Two different sorts of weapons, S-300 is a strategic SAM while Buk is a division level SAM.
Up to date versions of Buk have impressive performance but their role is different.
My earlier suggestion regarding the possible use of a long range SAM such as the S-300 was due to being mislead by a map posted on the first page that showed that radio contact was lost just off the Turkish coastline near the Cape of Akinci.
It is becoming clearer that the plane was hit in Syrian airspace, so the question that needs to be asked is why was it there rather than what hit it.