Hi Manuel,
I would recommend waiting a few weeks before you upgrade to AtoM 2.5 - the community has reported a few
high priority 2.5.0 bugs that we are planning to address with a 2.5.1 patch release. We'll announce the 2.5.1 release in this forum when it's ready.
When you are ready, the upgrade process for Windows should be very similar to the standard upgrade process:
https://www.accesstomemory.org/en/docs/2.5/admin-manual/installation/upgrading/#installation-upgrading. Please note that Artefactual can't provide technical support for Windows installations of AtoM on this forum, so if you have issues with your upgrade you'll need to rely on help from other community members that have experience with Windows installations. As with any upgrade, I would recommend you always make a backup first, and have a plan to revert to your current software version if the upgrade doesn't work.
The biggest change in installing AtoM 2.5 compared to AtoM 2.3.1 is that the required version of Elasticsearch has changed from Elasticsearch 1.x to Elasticsearch 5.x. AtoM 2.5 also supports PHP 7.x, so we recommend upgrading from PHP 5.x.
Best of luck!