When you are about to upgrade ZendTo using either the command
sudo apt-get upgrade zendto
yum update zendto
there are a few files you may want to save first, in case your configuration changes get overwritten by mistake when upgrading the package.
The files to save out of the way are as follows:
Important Note for Upgrades to Version 5: The files in /opt/zendto/templates have changed a lot from all previous versions. I strongly advise you simply move all your old versions of those files out of the way and leave it empty for the apt/yum upgrade to fill with brand new ones. This also applies to /opt/zendto/www/css/local.css.
Note that all of these files are intended for you to modify if you wish to, and they are all marked in the packages as being "configuration files" that should not be overwritten during an upgrade. However, particularly when using Ubuntu, it is very easy to accidentally overwrite them with the unconfigured new version of the files. So this is just to be extra cautious.
There are tools /opt/zendto/bin/upgrade_preferences_php and /opt/zendto/bin/upgrade_zendto_conf which will copy your existing changes to preferences.php and zendto.conf into the default new one supplied with the upgrade.
Important Note for Upgrades to Version 5: You must use both of these tools to upgrade your configuration files, or else your ZendTo version 5 installation will most likely not work.
Just run either of the tools on their own to see how to use them. Always tell them to send the output to a new file (after the ">"), not to your existing preferences.php or zendto.conf file!
In version 5, you will find there are now very few settings in zendto.conf. To learn how to customise the text and user interface in version 5 (beyond what you can still do in zendto.conf), please see the translators help page. It's actually really simple, I've set everything up for you to make it as easy as it can be.
Even if you are working in US English (the default language of ZendTo), you now change text in the user interface by providing a "translation" of the original piece of text, so that your "translation" contains your new (quite possibly still English) text.