TLDR: signal content in Apple notification can be retrieved even after signal app deletion.
I saw from this reddit thread: Signal messages retrieved from iPhone after uninstalling app. : signal
Referencing this news article: Pretti Killing May Affect ICE Prairieland “Antifa Cell” Terrorism Trial
The mention of signal is in court documents here: March 10: Federal Trial Day 12 - Support the Prairieland Defendants
Signal chat evidence from Sharp’s device (Exhibit 158):
Messages were recovered from Sharp’s phone through Apple’s internal notification storage — Signal had been removed, but incoming notifications were preserved in internal memory. Only incoming messages were captured (no outgoing).


Signal has supported this for many years. Users can choose full content notifications, name only, or no-content notifications.
I believe what’s in the payload is not the same as what the user chooses to see. That is, it’s sent no matter what but the user can set what’s visible on the lock screen. I could be wrong though.
That’s a separate OS setting. Signal itself has its own setting for which content is actually sent in the notification.
Why do you so confidently assert things which you do not know but merely believe without checking?
Did I not qualify it by saying I could be wrong? What is so confident about that? Jesus Christ, nobody asked you.