"Maintained" means different things for different projects, but in general if something is available in the Software Center, then it was maintained on some level, at the time of the Ubuntu release you're running on.
Many of the applications and libraries will never see updates throughout the life cycle of an Ubuntu release, simply because they are not necessarily maintained by specific people in Ubuntu, and do not get much attention. These tend to be in the universe archive, which you can disable (or enable) in the Software Sources properties from within Software Center. Some of them may get bug fixes, but don't expect much.
Only apps which are "supported" are definite candidates for fixes. This is mostly the "main" archive of the Ubuntu repository, and there are some things in universe as well.
Every program in the Software Center is maintained for as long as the distribution is supported. You can check the date limits on Wikipedia.
However, a program is not usually upgraded to a new version, and only bugfixes and security fixes are allowed for as long as you stay on the same Ubuntu release.
Sometimes, when there's a strong reason to do that, updated versions of the packages are published on ubuntu-updates repository (you should have it enabled by default, so don't worry). These updates are usually uploaded after a bug request on Launchpad that gains some popularity. For example, this about Inkscape on karmic.
There are some (not too much) exceptions, as Thunderbird and Firefox, that are always updated to new versions.
Open the USC
Find the app in question:
Example Gparted
you can see the installed date. If I were to scrolldown I can now see the add-ons the version and the updates from the source as well as reviews.
If you click on history, you now can view the installation dates as well as any updates
"Maintained" means different things for different projects, but in general if something is available in the Software Center, then it was maintained on some level, at the time of the Ubuntu release you're running on.
Many of the applications and libraries will never see updates throughout the life cycle of an Ubuntu release, simply because they are not necessarily maintained by specific people in Ubuntu, and do not get much attention. These tend to be in the universe archive, which you can disable (or enable) in the Software Sources properties from within Software Center. Some of them may get bug fixes, but don't expect much.
Only apps which are "supported" are definite candidates for fixes. This is mostly the "main" archive of the Ubuntu repository, and there are some things in universe as well.
Every program in the Software Center is maintained for as long as the distribution is supported. You can check the date limits on Wikipedia.
However, a program is not usually upgraded to a new version, and only bugfixes and security fixes are allowed for as long as you stay on the same Ubuntu release.
Sometimes, when there's a strong reason to do that, updated versions of the packages are published on
ubuntu-updatesrepository (you should have it enabled by default, so don't worry). These updates are usually uploaded after a bug request on Launchpad that gains some popularity. For example, this about Inkscape on karmic.There are some (not too much) exceptions, as Thunderbird and Firefox, that are always updated to new versions.