Is one required to convert any database used with previous SQL server version when using with newer one i.e 2012

Is one required to convert any database used with previous SQL server
version when using with newer one i.e 2012

I am setting up a dev environment on a my local PC, however when deployed
the project I am working on will be using SQL Server 2010. Could I install
SQL server express 2012 for local testing and not have to convert the
older version database(s) for use with it? Which if I recall correctly
would then not allow me to use them with SQL server 2010 ?