In the CoreSettings.config file you may noticed some settings that uses "upgradeif" setting. For example:
<customSetting key="MaxConcurrentSlowMsgsThreadPoolSize" type="local" value="4" upgradeIf="gt" />
upgradeif indicates if a core setting will be updated during upgrade (by default settings are not upgraded, only new ones will be inserted).
There is 3 options now:
gt – the setting will be updated to new value if old value is greater than new
lt – the setting will be updated to new value if old value is less than new
ne – the setting will be updated to new value if old value does not equal to new
“gt” means that our value will take over the customer’s if its greater than it, i.e. if there was a value of “2” previously, but our new one is “4” in 7.5 with this option – we will override. But if customer set it to 10 before, and ours only 4 – we will not change.