This question comes up infinitely and has been answered many times. We should probably create a canonical question for this.
After a release goes End of Life, there are zero updates to the repositories. Eventually after End of Life, the repositories for that release get migrated to oldreleases, which only holds the archive state as it was at the EOL date.
You will not get any security updates or bugfixes if you continue to use an EOL release. It is highly advisable that you upgrade from 14.10 to 15.04 after it EOLs (and after 15.04 is released), or that you use the LTS release (14.04) if you plan on not upgrading your Ubuntu version every interim release.
The problem with EOL releases is you have to either do a fresh install (to an LTS) or an in-place upgrade (to 15.04 after it is released).
If you do a fresh installation, you'll lose everything unless you back up your files, and you will still likely not have everything that 14.10 had in it.
If you do an in-place upgrade to 15.04 after 15.04 releases, you can keep most of your settings, but some programs might have dropped away. You have to examine the upgrade tasks closely before hitting "OK" on the upgrade. Do note that with upgrades, bugs and other problems can arise.