I’d recently asked the AiM folks about differences and I’ve attached the response and document.
Blockquote
Hi Harjit, there are differences on some internal revisions of the Mychron5S, those changes are not publicly documented in full by our manufacturing parent of AiM Sportline of Italy, but there are some notes of the changes in the links below. The newest versions are being produced with a change in processor starting with SN:83040000
Regarding instructions, these two links should have most of the information you might need. https://www.aimsports.com/us/products-kart.htm https://www.aimsports.com/us/documentation-products.htm#mychron5
The latest firmware version for the Mychron5S is 02.40.52.
this is really good information. i just went and bought a new one for $600 with a $40 rebate to buy a mount and new number plate. so it seems they have been secretly updating their newer models
I usually have my own mount for it on my seat post! i get one every race. i leave a form of id for exchange of a transponder then after the race i give it back and get my id back! find it nice to have my own mount!
isnt it free? When you arrive on race day you trade your id for one and then you leave it at the end of the day and you get your id back and its 100% free = )
Usually tracks that have “free” transponders, just build the rental fee into the racing fee. Be prepared when you go other places, as most do charge a fee for renting them. Basically, your paying for it one way or another.
I do 1 serier in sweden its mkr entry fee is 80 euro.
Then its my job to get my team new tires good engine etc, but every race i think transponder rental fee is in that 80euro and a race weekeend costs from everyting from 400 to 1200euro depends on how it goes and if stuff brake!