Due to Bohemia releasing a broken update (1.96) and saying they won't have a fix out for at least another day (see below).
Here is how you download to 1.94 in order to continue playing on the server...
Step 1
Open the beta properties tab of arma 3 properties inside your steam launcher.
Step 2
Enter "Arma3Legacy194" into the beta access code input, then press check code.
IF THE CODE DOESN'T WORK - Restart steam and try again
Step 3
Select the Legacy Build (1.94) dropdown from the list above the input.
Step 4
Wait for your arma 3 to update to the legacy build. Then launch and play like normal. We will make an announcement when we're ready to move back to the latest stable release branch of arma 3.
Dwarden from Bohemia Interactive's latest update.