Step 1: Enable Online validation
See Online validation Configuration to enable online validation.
Step 2: Add "Mobile Document Type"
Make sure a document type exists and points to a processing codeunit.
Pleas use (or take inspiration from) Codeunit 6181379 "MOB WMS Whse. Inquiry"
Step 3: Add "Mobile Document Type" to "Mobile Group"
Press the "Groups" action and add the new type to the relevant groups.
Failing to do so will result in the following error:
Step 4: Write you validation code
Edit your processing codeunit.
If the validation succeeds return the OK message:
MobBaseToolbox.CreateSimpleResponse(XMLResultDoc,'OK');
If the validation fails, create an error:
ERROR(MobWmsLanguage.GetMessage('UNKNOWN_LOT'),LotNumber);