Just a guess, but I'm assuming you're not on the latest version of Phoenix. Mine says something similar. I'm using Google Play to update my apps, if  @Compromised is using Obtainium or zap.store, he might be a bit ahead in versions 

 I don't see the update yet - this is exciting though!!!  

 Zap store here.  

 Mine wasn't ready in my pending updates but when I just manually found the app in my list of apps, i was able to update  

 Yeah I used Obtanium 

 Ups! 🙈