[O] How to safely update from ver. 8.2.10 to 8.3.x

[Maria Shinoto]

Hi all,

this weekend I got through lots of troubles, because I updated my 
orgmode version with "manage emacs packages" menu command and somehow 
got mixed preferences.

Now, after a clean install, I have org mode 8.2.10 and would like to
update to version 8.3.x (20160808) which is shown under the menu command
"manage emacs packages".

How can I do this safely, without creating a mess again?

Thanks for all advice,
Maria