When is this feature getting released https://medium.com/fresha-data-engineering/starrocks-incremental-mv-a-bridge-over-shifting-ice-759df57bc720

Incremental materialized view support on Iceberg is a feature on StarRocks 4.1 (to be released in March)

Does it also support MV built on top of native SR tables (shared-data arch)?

for native table support would be 4.3

Also for iceberg support be aware that is does not work on iceberg tables that are being compacted (yet).