The first Frostfell was in 2006, when TSS was current. I believe that's when it unlocks on the TLPs. While a few of the quests are in lower-level zones, some do require access to TSS-era content.
The Frostfell quest that starts in Timorous Deep is available (well, 1 of the 3 can be completed currently) and rewards stat food that's ridiculously out of era. Worth it if you're bored and have a half hour to kill.
Hope they remove this, it's do dumb that we get Stat food with a recommended level of 90 that out shines anything we will get for YEARS.
