In an extra large squad named on Monday, City players Robert Earnshaw, Danny Gabbidon and Rhys Weston were all called up for the full squad. James Collins is in the U21 squad.
As this game is not on a full international date, this will not affect any City fixtures.
The U21s take on their Serbian counterparts in Novi Sad on Tues 19 Aug (8pm ko local time), while the seniors play at the Red Star Stadium in Belgrade on Weds 20 Aug (8.15pm ko local time).
There will be around 650 Wales fans making the trip to Belgrade in a couple of weeks. Then there is the small matter of a massive game with Italy on 6 Sept, where several thousand Wales fans will travel to Milan. This will doubtless mean the home league match with Watford on 6 Sept will be postponed.
Congratulations to all the City players called up for international action, and good luck to Wales.