Emacs sees the directory with the new org-mode version, but loads the old version

The version of org-mode that came with my version of Emacs (24.5.2) is 8.2.10. I have installed version 8.3.1 from ELPA and added this to my init file:

(add-to-list 'load-path "~/.emacs.d/org-20150803")
(require 'org)

When I check the version of org in Emacs, it says:

Org-mode version 8.2.10 (release_8.2.10 @ /home/meir/.emacs.d/elpa/org-20150803/)

That is, it reports the old version and the new directory... (the built-in version is located in /usr/local/share/emacs/24.5/lisp/org)

I have tried the solutions proposed here and here.

Here is the relevant portion of my init file (there is nothing before this portion):

(require 'cl)

;; Org-mode that was shipped with Emacs
(setq load-path (remove-if (lambda (x) (string-match-p "org$" x)) load-path))
;; ELPA
(setq load-path (remove-if (lambda (x) (string-match-p "org-20" x)) load-path))

(add-to-list 'load-path "~/.emacs.d/org-20150803")

(require 'package)
(add-to-list 'package-archives
             '("melpa" . "http://melpa.milkbox.net/packages/") t)
(package-initialize)

(require 'org)

How do I get Emacs to load the new version of org-mode?

UPDATE: I renamed /usr/local/share/emacs/24.5/lisp/org to be /usr/local/share/emacs/24.5/lisp/org1, so Emacs for sure cannot see the built-in version. However, it still shows the old version number!..

Solution

I recommend you start over by deleting any personally installed versions of org:

rm -rf ~/.emacs.d/elpa/org-* # your installation path _may_ vary.

and then

ensure that when you build org from elpa you have not already loaded org.
decide which version of org you want and the package archive from which it comes.

For instance, if you, like me, want org-plus-contrib from http://orgmode.org/elpa, first you should:

> emacs -Q -batch -eval "(progn (require 'package) (add-to-list 'package-archives '(\"org\" . \"http://orgmode.org/elpa/\"))  (package-initialize) (package-refresh-contents) (package-install 'org-plus-contrib))"

Then, confirm success by quitting emacs and restarting as:

> emacs -q -eval "(progn (require 'package) (package-initialize))" 
meta-x org-version

Notes:

if you do NOT include -eval "(progn (require 'package) (package-initialize))" then org-version will likely be autoloaded from whatever you have installed in .../site-lisp - probably an old version
regular 'org package is also available at http://orgmode.org/elpa - c.f. http://orgmode.org/elpa.html for differences