Most devices support firmware upgrades.

It will be possible to add those features that do no require hardware support (and whose code fits into the memory of the device):

Parameter exchange defines methods to inquiry device capabilities, such as supported controllers, patch names, instrument profiles, device configuration and other metadata, and to get or set device configuration settings. Property exchange uses System Exclusive messages that carry JSON format data. Profiles define common sets of MIDI controllers for various instrument types, such as drawbar organs and analog synths, or for particular tasks, improving interoperability between instruments from different manufacturers.

Profile and Property Exchange (both in the MIDI 2.0 Ecosystem) can quite happily run over SysEx on the MIDI 1.0 Protocol.

So a device could add these features via a firmware update even if they only had 5 Pin Din Plugs (as an example).