I am just looking for the differences between the old version from Enterprise and the new Expert? Specially I want to know the differences between communication and protocols compared to the old version?

That is a big subject.

I suggest you start with the “Product Support Information”. In MIP Documentation pick Protocol integration, in the left hand side you the see “Product Support Information”.

Underneat this there is documentation for the protocols..

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One notable change is that basic users are not the same - https://force.milestonesys.com/support/articles/en_US/FAQ/MIP-SDK-applications-and-basic-users-in-XProtect-Corporate-or-XProtect-Expert