Distribution upgrades/jessie stretch
Feel free to add sections by service/package name or your own more details report on a subpage.
Jessie to Stretch in-place upgrade has only been tested once in labs. Please do this at your own risk. This page mostly assumes you are migrating to a freshly installed instance.
Also see this useful version table on debian.org.
On stretch libapache2-mod-php7.0 may have to be installed explicitly, while libapache2-mod-php5 was pulled in as a dependency automatically in the past.
- mysql-server-5.5 have been replaced with mariadb-server in stretch.
- mysql-client-5.5 have been replaced with mariadb-client in stretch.
mysql_ functions in PHP
The MySQL extension of PHP is deprecated and does not exist in PHP7 anymore. This means if you have any mysql_connect(), mysql_query() or any other function starting with "mysql_" in your PHP code, it will stop working on stretch. You have to switch to either PDO or mysqli. Also see here and here.
- php5 has been replaced with php7.0 in stretch
php5-cli does not exist anymore and is replaced by php7.0-cli.
php5-mysql does not exist anymore and is replaced by php7.0-mysql.
instance upgrade reports
- Phabricator daemons will fail to launch and phabricator will fail to work unless php 7.1 is installed.
- php7.0 is not supported in phabricator. Only 5.6 or lower and 7.1+.
Wikistats uses a typical LAMP-stack. Apache with PHP and MySQL so it can serve as an example for that.
Things that had to be done:
- php5-mysql had to be replaced with php7.0-mysql 
- php5-cli had to be replaced with php7.0-cli 
- libapache2-mod-php7.0 had to be installed (while libapache2-mod-php5 was automatically pulled in as dependency before) 
- I had to remove all mysql_ functions from PHP code and replace it with PDO. The deprecated MySQL extension does not exist anymore in PHP7. 
(note: I did not have to do anything about MySQL packages because i am already using MariaDB in this project. If you use MySQL you also need to switch and see above)