"not available on 6.x/edge" when trying to upgrade from 5.4.10

[k-ahn]

Summary

snap info rocketchat-server shows me an option to upgrade to 6.4.5, however, when i run snap refresh it states snap "rocketchat-server" is not available on 6.x/edge

Running Ubuntu 18.04.5 on a Pi 4. I am about to get cut off in 7 days so either need a solution or i'll need to write to users and discontinue the service. Help!

Detailed Outputs

snap refresh rocketchat-server --channel 6.x/edge

error: snap "rocketchat-server" is not available on 6.x/edge but is available to install on the
following tracks:

latest/stable snap refresh --stable rocketchat-server
latest/candidate snap refresh --candidate rocketchat-server
latest/beta snap refresh --beta rocketchat-server
latest/edge snap refresh --edge rocketchat-server
5.x/edge snap refresh --channel=5.x/edge rocketchat-server
4.x/stable snap refresh --channel=4.x rocketchat-server
4.x/candidate snap refresh --channel=4.x/candidate rocketchat-server
4.x/beta snap refresh --channel=4.x/beta rocketchat-server
4.x/edge snap refresh --channel=4.x/edge rocketchat-server
3.x/candidate snap refresh --channel=3.x/candidate rocketchat-server
3.x/beta snap refresh --channel=3.x/beta rocketchat-server
3.x/edge snap refresh --channel=3.x/edge rocketchat-server
2.x/candidate snap refresh --channel=2.x/candidate rocketchat-server
2.x/beta snap refresh --channel=2.x/beta rocketchat-server
2.x/edge snap refresh --channel=2.x/edge rocketchat-server

Please be mindful that different tracks may include different features. Get more information
with 'snap info rocketchat-server'.

snap info rocketchat-server

...
channels:
6.x/stable: –
6.x/candidate: –
6.x/beta: –
6.x/edge: 6.4.5 2023-11-08 (1591) 359MB -
latest/stable: 3.18.2 2021-12-06 (1495) 217MB -
latest/candidate: ↑
latest/beta: ↑
latest/edge: ↑
5.x/stable: –
5.x/candidate: –
5.x/beta: –
5.x/edge: 5.4.10 2023-11-08 (1590) 309MB -
4.x/stable: 4.1.2 2021-12-15 (1496) 212MB -
4.x/candidate: ↑
4.x/beta: ↑
4.x/edge: ↑
installed: 5.4.10 (1586) 299MB -