As semantics is gaining more ground in KNX and in the world of home and building automation in general, it needs to be avoided to submit a product for KNX registration that has a group object supporting multiple different main types, e.g., a group object with an unsigned value such as 7.001 (U16) AND a float value such as 9.001 (F16) at the same time. It is therefore paramount that already during the product development phase, this is taken into account and the necessary is done to create additional ComObjectRefs in the Manufacturer Tool to avoid the problematic situation as depicted in the example here below (e.g., two objects containing each 2 different main types)
A transitional period in which one can deviate from the above rule, will soon be communicated to KNX manufacturers.