On an Azure SQL Database V12 server, the maximum compatibility level for a database is 130. This same maximum applies on Microsoft SQL Server 2016 (currently at pre-release CTP3).
A new database on SQL Database V12 is set to level 120, but you can increase its level to 130. On V12, compatibility level 130 is currently supported as preview, and not yet as generally available.
An upgrade of a V11 database to V12 will not alter its compatibility level, although you can alter the level manually.
For details about the effects of 130, 120, and other levels, see ALTER DATABASE Compatibility Level (Transact-SQL)