The latest version of PHP used in Squeeze is 5.3.3.
Add Squeeze repositories to your source list:
deb http://archive.debian.org/debian/ squeeze main contrib non-free
deb http://archive.debian.org/debian/ squeeze-lts main contrib non-free
Refresh package list:
apt-get -o Acquire::Check-Valid-Until=false update
Delete the current version of PHP:
dpkg -r --force-depends $(dpkg -l | grep php | awk '{print $2}')
Install the same PHP packages using repo compression:
apt-get install -t "squeeze" $(dpkg -l | grep php | awk '{print $2}')
Note. I use this to downgrade PHP from Squayze's PHP 5.3 to Lenny PHP 5.2, it should work from Jessie to Squeeze.
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