I was trying to use a 7Artisans 28/1.4 M fit lens on my M240. I went into manual lens selection, with the expectation of being able to declare it as a 28/f1.4 Summilux, only to find that this lens was not listed, unlike on my SL and CL. On checking, I found that the latest firmware release, 2.0.5.0, dates from around 20 months ago in November 2017 and does not seem to allow for a number of the latest lenses such as the 28 Summilux. I also noticed that a number of the links on Leica's download page for the M240 are dead or inactive (take you to a blank page). It would seem that the M240 is now being written out of Leica's consciousness, even though it is still listed as a current product. It cannot be a big rewrite of the firmware to add additional lenses if the firmware was well written in the first place, as this should have been allowed for.
On the basis of past experience, it is an extremely laborious process to get Leica to listen when they have made firmware errors and/or omissions and can take up to 2 years to get these corrected, after Leica have admitted that they have made an error or omission. The GPS error on the multifunction grip is a good example of this, when GPS was pretty much disabled by an FW update error and it took 2 years for Leica to correct it, in spite of many reminders from me and others.
Wilson