Spring RTS Engine

Is there a way to prevent SPADS from auto-reloading configuration during update period (i.e. one host used for testing, the rest waiting on old version)?

I'm not sure I understand what you want to do.
If you update the SPADS binaries for one SPADS instance, then your other instances launched from same SPADS installation directory will use these new binaries when they restart anyway, so they need the new conf...

when they restart yes, but I want to prevent old (running) binaries from using the new configs.

They won't reload the config unless they restart (for automatic update for example) or you issue a !reloadConf

You have to set the autoRestartForUpdate global setting to "off" if you don't want your other autohosts to restart automatically when they detect their binaries have been updated.