Hi, this is a problem I have already experienced (and reported) with past Grandstream devices.
I have exported an existing contact list from another device (GXV3275) in XML format and imported into the GRP2614. Only those entries that have both first name AND last name appear in the correct sort order. Those with either missing first or last name appear in a complety ramdom order, so it is impossible to navigate the phone book on the device.
I think this is a real life problem - you will always have entries with first name only (colleagues, etc.), and with last name only (first name unknown, or it’s a company name).
The solution would be easy I believe: If you take a string composed of “firstname+lastname” as sorting criteria, it will work for all cases.