Typically, between major releases, there may be minor releases which fix some common problems or add a much needed feature that can't wait for a major release. These minor releases are usually available as updates.
Note that workspaces can be carried over to a new release and that will also carry across your workbench settings. However, new releases sometimes require the workspace to be upgraded in some way, so it is recommended that you backup your workspace before opening it in a new release of MyEclipse.
Updates are automatically checked for (unless turned off in the Install/Update > Automatic Updates preferences page). If there are updates, you will see the following info pop-up:
Click Apply Updates to apply the updates.
Alternatively, start MyEclipse then click Help in the main menu bar and select "Check for Updates...". This will start a check for updates to MyEclipse and, eventually, the following dialog will be shown:
If there are updates to other plug-ins that you've installed, these will also be shown. To apply MyEclipse updates, just press the Apply button, for other updates, press the Review button:
For major releases, the version of eclipse platform that underpins MyEclipse is usually different from the previous major release. For this reason, you should install a new major release as a fresh installation. This can be done through pulse or with a custom or off-line installer. You do not need to uninstall the previous release to install a new release of MyEclipse - just install to a different location (usually, the default location is adequate).
If you have installed through pulse, similar techniques are used with the pulse explorer.
See the How do I perform a clean MyEclipse install
FAQ for more information on installing MyEclipse.
Note that for releases prior to 2013, the following steps should be taken.
Start MyEclipse then go to the Configuration Center (via Help->MyEclipse Configuration Center). Click on the Software tab and wait for updates to be checked. During this checking process, there will be the message, "Finding available updates...", in the "Software Updates Available" panel. Eventually, the panel will contain the updates that are available. Select the update or updates that you wish to install and press the Apply button in the "Pending Changes" panel. This will lead you through the rest of the upgrade process.
Please read Pulse & MyEclipse Configuration Center for more information on the changes since 2013