FabFilter Timeless 3 is available in both VST 2 and VST 3 formats. They can be installed and
used both at the same time. The VST 3 format
offers easy side-chaining and
is more CPU-friendly in some cases, but it can only
be used by hosts that support it, for example recent versions of Cubase, Studio One or FL Studio.
The VST 2 format is compatible with a larger variety of hosts.
Both the VST 2 and VST 3 versions of the plug-in automatically adapt themselves to the channel
layout of the track they are inserted on (mono/stereo).