I think its confusing because they labeled the fresh servers as new servers and it wasn't the best word to use.

SE has implied many, many, many times that the servers for 2.0 are going to be new servers.

Remember all the times you saw:

With current server its not possible.
This will be possible in 2.0 with new server and planning to do.
This may be hard to implement with current server.

The reason for this is that SE probably used the old decommissioned FFXI servers for FFXIV, which are reeeeeally old now. Remember a game world is just a cluster of data, its not an actual server. (Its just housed on one via the host client) Therefor that data can be moved relatively easily. Remember SERVER is not mutually inclusive with WORLD. Lets say Server1 is housing Durandal and Server6 is housing Sargantanas; its possible for them to move Durandal to Server6 and Sargantanas to Server1 by using an intermediary. Just because the Worlds are on certain servers now doesn't mean they can't move off.

At my work we have changed servers multiple times. What happens is the data is mirrored onto the new server, but due to a better server software and obviously better hardware it runs much much quicker. Also many of its basic functions increase in output (this is probably why the "will be possible in 2.0 with new servers" appeared a lot).

For example our old server had a SQL table limitation of 80 items. When we swapped to new hardware+software the SQL table limitation increased to around 240 (not sure exactly because we haven't made anything with that many items so far).

So by basic logic one assumes ARR cannot run on the servers which are currently in use because of the limitations, so therefor all servers for 2.0 will be either brand new servers or the current servers with updated software but I would assume (omg I know you guys hate assuming tho the ones that hate it do the most) that all servers will be new for 2.0.