Yes, there are four Data Interoperability formats that can have a DGN file name extension, three Microstation editions plus Intergraph MGE.

If you are referring to Bentley's new "i-Model" file format (well, it isn't as new as I thought but new is relative here), then the answer is that neither FME nor Data Interop can read it ... yet.

We have a reader under development in house currently. If you were able to send some sample files into support@safe.com, we'd be pleased to try them out with what we've got thus far.

Our goal is to release i-Model reading with FME 2018, and with the next Data Interop that comes out after that.

(My source for guessing that .i.dgn is the i-Model extension is this post here https://communities.bentley.com/products/w/products__wiki/3344 )