The file that I get from the official Adobe website is in the tar.gz file format. I tried the "standard" way of installing software with that extension, which wouldn't work.
Also, installing using Canonical's repo gives me version 11.2, which is very outdated.
You simply need to install the
adobe-flashplugin
package from the Partner repository.Note that the version shown in chrome://plugins will still be 11.2.999.999 and not 23. This is also true if you download the file from the page linked to in your question and place the libpepflashplayer.so file in the system folder.
However, if you visit https://www.adobe.com/software/flash/about/ it should show that you have version 23.
Canonical's repo currently installs version 11 of the NPAPI plugin and version 23 of the PPAPI plugin, so no, the PPAPI it installs is not outdated at all. (Soon it will start to install an updated version of NPAPI as well.)
Accordingly, all you need to do is enabling Canonical Partner and installing the
adobe-flashplugin
package.ADOBE BEGINS TO SUPPORT LINUX IN EXPERIMENTAL WAY
I managed it to work in the following way.
Create a directory in your user directory like
pepper
go to http://get.adobe.com/flashplayer/otherversions/
in the first step pick up Linux32 or Linux64 (according to your installation achitecture)
in the second step in dropdown list; pick up
FP 23.0 for other Linux ..
download the archive, and extract contents of tar.gz into
~/pepper
and run your chromium from terminal