Impact of changing the DB compatibility level for a Published replicated DB from 90 to 100
You can follow below steps :


Make sure that the Log Reader Agent is running for the database. By default, the agent runs continuously.
Stop user activity on published tables.
Allow time for the Log Reader Agent to copy transactions to the distribution database, and then stop the agent.
Execute sp_replcmds to verify that all transactions have been processed. The result set from this procedure should be empty.
Execute sp_replflush to close the connection from sp_replcmds.
Change the compatibility level of the database.
Start the Log Reader Agent.