This entry is used in combination with AllowReactivation to identify a machine.
The parameter defines the number of installation codes, which have to be identical, to identify a PC. MinIdenticalInstcodes = 3 would need at least 3 identical installation codes out of all available codes to identify the PC.
A good value to use is between 3-4.
For more background information and additional configuration options see: Che
Default value: no default value
See also
AllowReactivation - activate this option and detail information
CheckInstcodeType - alternative configuration setting
IgnoreLocalInstCodes - additional configuration setting