LEICA lenses can be upgraded with 6 bit coding for automatic recognition in LEICA cameras. It is a convenient upgrade that takes 15 minutes.
Urth Leica R to Leica M Lens Mount Adapter
LEICA ELMARIT-M 90mm f/2.8 - Losing a Stop and a Burden - MPRECKE
Adding 6-bit Coding to LEICA M Lenses - MPRECKE
TTArtisan Unveils Leica M-Mount to Sony E-Mount Lens Adapter
Fuji FinePix X Series and Leica Accessories - Match Technical
A Look at: Novoflex Leica M Lens to SL-T Lens Adapter - Finding Range
Leitz and Leica Lens Compendium & Leica Serial Numbers - Thorsten
Bernd Margotte Photography
The Leica M10-P White Edition - MPRECKE