Welcome to Android Central! That phone was released in Jan 2016, so considering it's >2 years old, I doubt it will get any more updates. What do you mean by running slow when going to other apps? Do you mean it's slow to switch or open new apps? Do the apps run normally once they're opened? Remember that your phone is quite under-powered by today's standards, so I would expect it to be a little slow when opening apps, and app performance is likely to be subpar as well.