Nelson introduced chat fade with his 25 May 2018 patch. What this means is that you may miss important messages. The current workaround is to edit one line in your preferences.json file and restart Unturned. On Windows machines the file can be found in C:\Program Files (x86)\Steam\SteamApps\common\Unturned or C:\Program Files\Steam\SteamApps\common\Unturned Open preferences.json with notepad or any other basic text editor. You should see a line that says "Fade_Delay". The default value is 10. You can change this number to anything but if you want you chat to persist then set it to 1000 and save. Once you restart Unturned your chat should persist. I don't deal with Macs so a Mac user will have to give the default path of the file. I can then post it here. Thanks Nelson.
For those of you who are Mac users: Top of your screen you’ll see a set of options: Apple logo, Finder, Edit, View, Go, Window and Help. Click “Go”. Second from bottom of the options you’ll see “Go to Folder...” click that. You’ll see a text box, type in: ~/Library/application support/steam This will take you to the steam folder, click on the steam folder. Near the bottom there is “steamapps” click that. In there is “common” click that. Now you’ll see a list of games you have, at the bottom is “Unturned” click that. Here you will find a file named “Preferences.json” double click that. Within the text box in the second paragraph you will see “Fade_Delay” where it says 10.0 change to 1000.0 Before you close the text box at the top of your screen next to the apple logo and TextEdit you will see “File” click that. Near the top you’ll see save, click that. All done, close the text box and start up your unturned!