Within the UK and EASA land differences training is very basic and covers: VP (constant speed) prop, turbo charging, retractable undercarriage and tail wheel/tricycle undercarriage as appropriate. It is not a certificate or a rating. There is not a requirement to have a signature in the logbook other than to demonstrate that you have undertaken the training. Those pilots who had the experience prior to the rule are required to do nothing further and will not have a logbook endorsement by an instructor. It will be obvious to any authority, hirer or insurer however that they have the prior knowledge and experience from noting the aircraft they had flown previously.
Usually all or any one the above requirements will have been met during the conversion or familiarization training when one or all of the above is applicable. As already said there in not a syllabus nor at any time a requirement to do more, even should the differences be more complex on a later additional type. Of course I agree there is a lot more to do in many cases but this will hopefully be part of the training onto type. Even so only if the pilot is required to do additional training by the authority, hirer or insurer or chooses to do so.
An example is the TB10* which is very simple: max throttle to the top of climb with an adjustment to the prop on the way up, which will probably do later for the cruise. then fine for the landing. No further training in constant speed propellers is required by regulation however complex a later type may be.
* the parking brake is applied by applying the toe brakes, pulling on a black knob on the dash board,and then letting go. This is usually more reliable than the C150 parking brake.
Last edited by Fl1ingfrog; 7th Jan 2022 at 14:11.