[exceptionality]

Here's an example:
E81_#0910&EAAT%0300*UA11$1CA$205$258$2TM$321$428$441$473$493$494$4AK$502$520$522$530$548$701$7RP$842$845$850$853$863$891$8LR$8S3$ 8SD$8TL$8TN-B055

FRM: 9240525
How would you update it?

I guess using the kmmdata would be the correct way to determine the latest zbnumber based on vehicle order.

Under FRM functional adress(72) a string: UA11|UA12|UA31|UA32|UA51|UA52|UA71|UA72|UB11|UB12|UB31|UB32|UB51|UB52|UB71|UB72|UB91|UB92|UK11|UK12|UK31|UK32|UK51|UK52;522&-524&-XFRM;0909500-1006501,1009500-

should match the VO of the car.
UA11 typecode, with S522A, without S254A without XFRM, istep 09-09-500 unitl 10-06-501.

And the latest ZB is 9390481. The one You mentioned is one above, thus not the latest one.

Did i miss something?

P.S.
Data used was taken from ISTA-P 3.67