Substitution for AR150 and X300

Hi everybody, i work in a automation company without an IT internal department so we arrange how possible with a remote support for our customer.

Some years ago we bought enough device and we covered our product until today that we shipped the last box for a remote assistance. We bought the two devices in the object (AR150 and X300) where we installed the vpn services and used it has a bridge from us to our customer.

In those days i was looking for buying new boxes but i find out that they are out of production, so my question is: Which could be a good alternative?