OS X Yosemite

Hi,

I have a Macbook Pro that I bought about 4 years ago, it's running on OS X (10.6.8) and a lot of the apps are now outdated (i.e., Safari) and I can't seem to download the new version of it, because it's not compatible. If I were to download OS X Yosemite from the App Store, will it allow me to download newer apps and upgrade the system that I have? Also, for anyone who has done it, have you found any kinks to "upgrading" the OS X to Yosemite?

Thanks!