Yes, the version needs incrementing because you added a new virtual method to a public class. That changes the vtbl layout, so the change is not ABI compatible.
You will need to update the symbols file with the added symbols. Instructions for doing this are in HACKING.
The MICRO version in CMakeLists.txt needs updating.
In addition, debian/changelog needs updating. From the root directory (not the debian directory):
$ dch -v '0.4.8+14.10.20140519-0ubuntu1'
Note the 0.4.8 in the version string, which has to match whatever is in CMakeLists.txt.
Yes, the version needs incrementing because you added a new virtual method to a public class. That changes the vtbl layout, so the change is not ABI compatible.
You will need to update the symbols file with the added symbols. Instructions for doing this are in HACKING.
The MICRO version in CMakeLists.txt needs updating.
In addition, debian/changelog needs updating. From the root directory (not the debian directory):
$ dch -v '0.4.8+ 14.10.20140519- 0ubuntu1'
Note the 0.4.8 in the version string, which has to match whatever is in CMakeLists.txt.