Ubuntu – This flash plugin was blocked because it is out of date

This question is now obsolete since Chromium and its derivatives like Google Chrome use the more modern PPAPI Flash Player plug-in. It's built in to Chrome, but Chromium users need to rely on other solutions.

I being a developer want to use Flash version 10.1 or older on some of my Ubuntu machines. The problem is each time I run Google Chrome on this Lucid 64 bit machine (which is the only machine with me) I get a warning:

This flash plugin was blocked because it is out of date

As per instructions on these links:

• http://www.chromium.org/developers/how-tos/run-chromium-with-flags
• http://peter.sh/experiments/chromium-command-line-switches/

then I tried at a command line:

google-chrome --allow-outdated-plugins

But I still got the same warning. Is there a way I can use with an old version of flash plugin?

UPDATE 1
As per below suggestion I edited the hex value of one of the file

/usr/lib/firefox/plugins/flashplugin-alternative.so
/usr/lib/iceape/plugins/flashplugin-alternative.so
/usr/lib/libvisual-0.4/morph/morph_flash.so
/usr/lib/openoffice/basis3.2/program/libflashlx.so
/usr/lib/xulrunner/plugins/flashplugin-alternative.so
/usr/lib/flashplugin-installer/libflashplayer.so
/usr/lib/midbrowser/plugins/flashplugin-alternative.so
/usr/lib/xulrunner-addons/plugins/flashplugin-alternative.so
/usr/lib/mozilla/plugins/flashplugin-alternative.so
/usr/lib/iceweasel/plugins/flashplugin-alternative.so
/usr/share/ubufox/plugins/npwrapper.libflashplayer.so
/var/lib/flashplugin-installer/npwrapper.libflashplayer.so


which was
/usr/lib/flashplugin-installer/libflashplayer.so
From 10.1 to 10.2 but there was no effect.How do I find out which file is google-chrome using from above?

UPDATE 2
Following from lsof output I found

var/lib/flashplugin-installer/npwrapper.libflashplayer.so

is the flash plugin which google chrome is using and there I could not find the string Flash 10.1 as mentioned in reply below.