In this part of documentation you can read some informations and solutions for problems related to modules that are related to some configuration aspects or environment (hosting) settings of the shop. Fact that these topics are most common problems does not mean that your shop based on PrestaShop has or will have the same problem.
Everything depends on how often you update our modules. if you update the module regularly - its enough to just upload new .zip file to shops back office. if you update our modules from time to time it will be required to reinstall it.Below you can find details about update process - both for free and for paid addons.
Some part of MyPresta.eu modules uses overrides mechanism. In context of PrestaShop overriding is a way to "override" Prestashop's core files (class files and controller files). In simple words core files defines how PrestaShop works. So, with this kind of feature we can alter PrestaShop and a way of how it works.