MaximumConcurrentJobs has been deprecated in 24, but the default configuration still contain these deprecated settings. These should get removed.
We should also add a test (maybe a systemtest is possible) to check if the default configuration works without emitting a warning.

core/src/defaultconfigs$ git grep -i concurrent 
[...]
bareos-fd.d/client/myself.conf.in:  Maximum Concurrent Jobs = 20
bareos-sd.d/storage/bareos-sd.conf.in:  Maximum Concurrent Jobs = 20