Yes, we changed the resource production of many islands with the recent server update. Mostly mid-game and end-game islands were affected by this change.
Why did we do it?
We noticed that many players (especially higher level ones) were often sitting on full resource storages while waiting for their upgrades to finish. We received feedback from you guys that this didn’t feel very good. We understand that having full resources but not being able to upgrade anything is not very motivating. Our statistics showed that many players did less battles than before because they saw no reason to raid islands. Getting Gold and Wisdom (among other rewards) was always meant to be one of the main reasons why people fight battles so that they could work towards being able to upgrade their Olympus. It should feel satisfying to upgrade things in the game and being able to afford one of the big and expensive upgrades like the Heroes’ Temple should feel like an achievement.
The further you progress in the game the more time is required for every upgrade. We are very happy with those times at the moment (especially after we had reduced many of them some time ago). We think that the time it takes to finish an upgrade must not discourage you from actually playing the game. You should use this time to gather resources which you can spend on the next upgrade when one of your workers becomes available again. We want you to have a reason to fight battles and we want you to get rewarded for every battle you win.
Please be assured that we are closely monitoring our data after every single change we make. We also read your feedback and we would be happy to know your thoughts on the recent reduction of resource production after some time has passed.