We have introduced DateTimeOffset support for PostgreSQL provider in 5.0.11 RC. Here, we want to explain some restrictions of this RDBMS which affect our implementation of that type support.
We warn you that support for date/time with time zone is different from Oracle Database and Microsoft SQL Server implementations. The last two RDBMS has full support for all parts of date/time including time zone, but PostgreSQL doesn't.
If you want to use DateTimeOffset type in domain models on PostgreSQL storage we need to explain some things you may face with.