Hi @quattroman,
Is there any way to ensure the notification remains visible until manually closed.
I’m not sure it would be possible for Mailspring to dictate how long notifications stay on screen, as that’s generally managed by the operating system. You can change how long a notification stays on screen from Windows’s settings, under Ease of Access > Other Settings, but it looks like the maximum is 30 seconds.
Typically, the Mailspring tray icon is how you’d know if there are new messages.
Is there any way to get a push notification of either a new email arriving or an opened email - pushed to my mobile (Android or iOS).
As to push notifications, that’s not something we can do. Mailspring is a desktop mail client, and there are presently no plans to add iOS or Android support. See this topic for more on that: iOS or Android (Mobile) Support
As an aside, when I first started to use mailspring, I did receive new mail notifications from the associated Gmail account…but in recent months this has stopped.
That sounds like a bug. First, make sure Mailspring is still configured correctly (Configuring notifications), and if that does not resolve the problem, open a new Bug Report: Bug Reports - Mailspring Community