I have a master database running mysql 5.5.11, and I am planning to setup a new slave. I am planning to use the 5.5.30 as it is the latest version. For setting up new slave, I am copying files from master 5.5.11 version. Will there be any compatibility issues?
Your replication configuration
5.5.11 -> 5.5.30 is a supported configuration and there is no real justification for deploying a new slave using old software.
In fact, MySQL replication is supported across major releases as long as the two releases are consecutive, so
5.1.x -> 5.5.x is supported and
5.5.x -> 5.6.x is supported.
The only caveats are that the slave should be the same version as -- or newer than -- the master, and if you're doing circular replication, you should not have more than two versions of MySQL in the chain (and best practice suggests that they be identical in this case).
If you are copying the files from another machine of a different version, don't forget to run
mysql_upgrade on the new slave.
I guess it's good to have the same version at both ends. By good, I mean that 5.5.11 might have bugs that have been fixed in 5.5.30 with respect to replication, so I guess it's safer to use the same versions.
Of course, you can always try and test with your data. But test well. You can run this scenario for a few days to see if something comes up.