LCG 104 will have fmtlib 10 which is more picky than previous versions.
Note: this is part of a pool of related (not interdependent) MRs: Detector!400 (merged), LHCb!4143 (merged), !46 (merged), Boole!483 (merged), Rec!3449 (merged), Alignment!388 (merged)
See also https://its.cern.ch/jira/projects/LHCBPS/issues/LHCBPS-1912
