First, I want to thank you for an awesome tool - Grepolis wouldn't be the same without it.
The new world EN98 Rhodes just opened, and I manually added the world, and got data, "Database from 30.03.2017 to 30.03.2017". Later, I started GT, but no new data appeared for this world. When I moved and renamed the data\EN98 folder and restarted, I got data for "Database from 02.04.2017 to 02.04.2017", but 1 day later, the data is NOT updating again. All of my other worlds are correctly receiving new data with the current date. My version displays as 2.0.15, but I believe I installed the 2.0.16 update.
I am not sure what changed on this, but it appears to be receiving new data now. Perhaps it is related to the World being new. I will monitor, and report if any problems persist.
Sry for the late answer...i am not playing anymore. But you are right. There was allways a delay (~ a week or less) between the server start and the release of the data for external tools.