Playing through again since they updated for their 5 year anniversary. I stumbled across new dialog on a frequency 107 in Fort Milner when Jonas gets locked in the room upon investigating. The voices that come through are of the two new characters in Oxenfree II: Lost Signals. There is also a Morse code message at the end that translates to "Learn the truth". I will be exploring more into new/added content in this game and will keep you all posted! They added new content and features March 28th and from what I can find this is the first finding.