Sometimes I find IPX (or I-PEX or U.FL?), sometimes MCX, sometimes SMA... on descriptions
So I link them all here... so you can find out yourself
SMA wikipedia the most common one, it is threaded
MCX wikipedia snap in
IPX I-PEX U.FL wikipedia very tiny, mostly used on little pc board connections, surface mounted, snap on
For antennas, you could do an internet search with keywords: "868 MHz antenna"
Also YouTube is a nice source for searching all these terms
LoRa module video on YouTube at 2:00 minutes it shows internally U.FL connectors, and externally MCX if I am not mistaken