Stub Zone updates

Ally77

Can someone explain the differences and when to use each of the following please regarding stub zone updates ?

Reload - Reloads from local storage of DNS server

Transfer from master - Determines whether serial number in stub zones SOA has expired

Reload from master - Performs a zone transfer from stub zones master regardless of the serial number in the stub zones SOA Resource record

All seems the same to me. Thanks

Webmaster

Reload reloads the stub zone from the local DNS server's disk on which the stub zone resides.

Transfer from master - is like a regular periodic transfer but manual. The DNS server with the stub zone will only request a zone transfer from the master server when the serial number on the master server increased (i.o.w. only when something changes/when there are updates)

Reload from master - The DNS server with the stub zone ignores the serial number and performs a zone transfer from the master server.