Openfire update from 3.8.2 to latest version (4.6)

Hello everyone,
I’ve been trying to update our openfire servers, from 3.8.2 to the latest version (This being 4.6.0 today), and I’m running into a couple of problems:

When I tried updating it directly from 3.8.2 to 4.6.0 and starting the server, I got the message “Found old database version 24, updating to 32” (I’m translating it from Portuguese, so I’m not sure exactly what message it’d be in english). It takes a long time, processes all plugins and starts running, however, admin accounts and client logins stopped working.
I then thought that updating from such an old version might cause some problems (Who knows how many database changes happened between version 24 and 32), and so I decided to update the server one version at a time.

It all goes well until I reach version 4.1… 0? (If I remember correctly) When the database decides to update once again (From 24 to 25) this time. This time, admin and client logins still work, but extremely (unusable-like) slow. So I reverted back to the old 3.8.2 and kept it running whilst figuring out what’s going on; We’re at work hours and everyone needs Openfire to be running, and I forgot to take the logs, I’ll post them here once I start the process again in a couple hours (After everyone’s left).

Here’s what I’ve noticed so far:
There’s a table in the openfire database called “ofVersion”. Querying it returns a VERSION row with a value of 24 (Which I assume is where the server is taking its version). After waiting for the server to “update” the database, some new tables are added (namely, MUC related) but querying the “dbo.ofVersion” table still returns a VERSION value of 24; Indeed, stopping the server and restarting prompts it to attempt to update the database again, I have yet to understand what’s going on in there.

I must explain something, however: I migrated the Openfire database from MySQL to MSSQLS - The guy who set this up before me must’ve forgotten that we already have a SQL Server instance or something - The migration happened smoothly, with schemas and tables converting with 100% success to the SQL Server database I had created for OpenFire, and the server had no problems reconnecting with the database after I configured it to do so.
Can anyone shed a light on this, please?
Thank you all in advance,

(Edit: formatting. No one needs to read a wall of text with no decent formatting)