I'm still using WordPress 3.3.2.
Once I tried to update it to newer version, but this didn't work out well. I had changed some things in the HTML of the theme (Twenty Eleven 1.3), for example: I removed the text 'powered by WordPress' from the bottom of all the pages'. After updating WordPress, the changes had all been set to default again and I had to do it all over again.
Is it possible for me to update to a newer version of WordPress without losing all the changes I made??