from 7.6. to 14.6., players on RU server will be able to activate the Personal Reserves for the first time. They can be claimed from missions that looks as such:
Condition: Win 10 times while destroying at least one vehicle in each victorious battle
Reward: reserve - 5 percent XP bonus (for 6 hours, activated in personal reserves), can only be completed 9 times per account
Condition: Complete Mission 1 three times
Reward: reserve - 10 percent XP bonus (for 4 hours, activated in personal reserves), can only be completed 3 times per account
Condition: Complete Mission 3 three times
Reward: reserve - 15 percent XP bonus (for 2 hours, activated in personal reserves), can only be completed 1 time per account
These bonuses don't stack (eg. you can't activate medium and small reserves at small time for more XP). The reserves have to be activated until 1.9.2015 and it is not possible to stop an activated reserve.