Store datetime in UTC format now, and fix presentation of TZUTC. Also standardise message summaries on Notifications

app/Notifications/Netmails/NetmailHubNoUser.php

@@ -50,14 +50,7 @@ class NetmailHubNoUser extends Netmails
 		// Message
 		$msg = $this->page(FALSE,'Reject');
 
-		$msg->addText(
-			sprintf("Your netmail with ID [%s] to [%s] here was received here on [%s] and it looks like you sent it on [%s].\r\r",
-				$this->mo->msgid,
-				$this->mo->to,
-				Carbon::now()->utc()->toDateTimeString(),
-				$this->mo->date->utc()->toDateTimeString(),
-			)
-		);
+		$msg->addText($this->sourceSummary($this->mo)."\r\r");
 
 		$msg->addText("This hub is not attended, so no user will be able to read your message. You may like to try and contact them another way.\r\r");