Debian repository for EOL version

Update file /etc/apt/sources.list

deb http://archive.debian.org/debian <code_name> main contrib non-free

# For example
# deb http://archive.debian.org/debian squeeze main contrib non-free

Ignore check Release file expired

$ echo 'Acquire::Check-Valid-Until "false";' | sudo tee /etc/apt/apt.conf.d/90ignore-release-date
debian  apt