It’s an open secret that the Encore can hold the advanced cone burr from the Virtuoso+, called the M2 burr. We aren’t afraid to let folks know about this compatibility because there are plenty of folks who want a straightforward machine like the Encore, but love the grind quality of the Virtuoso+.
The upgrade is pretty straightforward: disassemble your Encore’s gearbox and install the burr. On re-assembly, you’ve completed the upgrade!
That being said, we hear a lot in Support about folks who were advised to check the gearbox version of their Encore for compatibility. This isn’t actually necessary, but we understand why folks ask – the Virtuoso+ itself received a gearbox upgrade in conjunction with the change to the M2 burr.
Back in the day, we only built three models: the Maestro, Maestro Plus, and Virtuoso. Each of these had the original gearbox version for this grinder family. In 2012, seeking to further improve our stalwart models, we updated the design of the gearbox internals and called it “GB2.0 for Gearbox 2.0”
Then, in 2013, the Maestro and Maestro Plus were discontinued, and basically consolidated into one model: the Encore. This means that every single Encore ever built already has GB2.0! 
So, if you own an Encore and are thinking about a nice performance upgrade, don’t worry about checking your gearbox version – you can install an M2 burr no matter how old the machine!