I'll give you my understanding of these things.
My first question is about usage of my current My Log file in 5.х.
Size – around 26 Mb, aircraft table – around 11000 entries. I placed this file in Data directory of 5.х instead of an empty one supplied with software. Moving between entries takes up to 10 seconds and the interface is not responsive during that time. Any ideas why?
This looks like a possible bug, that will be looked into.
1. Which exact criteria makes difference between manual and official entries? For example - if I change only AC field in the database, will this record be manual or official after that?
I don't really know what you mean by "manual" and "official" entries. If you mark an aircraft record with AUTOUPDATE="N", you're telling Radarbox not to update this record.
2. How can I identify differences between manual and official entries in my current 3.13/4.03 database?
Sort on the AUTOUPDATE field, or select records with N in the AUTOUPDATE field.
3. What is the exact purpose of Autoupdate field in the database?
If you set this to N, this affects two areas:
1. If you tick "Autopopulate Aircraft Data" in Preferences, records with N will not be updated as aircraft are received, unless you also tick "Auto Update Manually Changed Records".
2. In the Database Update section of Database Explorer, if you select "Do not update manually changed records", records with N will not be updated.
4. What is Autoupdate?
Autoupdate happens in real-time as aircraft are received in your MyFlights list, or you click on an aircraft in the Networks list. It populates the aircraft record, and downloads thumbnail photos.
5. If I use only Auto-Populate buttons in the Preferences Menu and Populate button in MyLog windows may I expect that I will have Navdata updates in “3.13/4.03 old-fashion” way?
Yes, that's my understanding.
My third question is concerning my current photo base usage in 5.x.
My base consists of more than 32000 photos carefully selected during the years having started from AirNav ACARS decoder times and being regularly updated (and published here). But as far as I understand now we need to have PPTN and PPTN2 fields in Navdata filled to have the photos displayed. How can I have my current photo base working after software upgrade to 5.x? By making thousands of entries in NavData base manually?
This is a good point and reinforces something I've already asked Airnav to consider. I would like v5 to do as follows. If PTTN is blank, then look for a thumbnail file with the same name as the aircraft registration. Ditto for PTTN2. I will raise this as a Feature Request - FS#258. Also see point 2 at
http://www.airnavsystems.com/forum/index.php?topic=7522.msg89996#msg89996Any questions, just ask and I'll try to help.