"New software is available"...

Are you seeing this in the system tray every time you log in to your computer? It's pretty annoying. There's even a Microsoft User Voice entry for it.

There is a workaround - set all your application deployment User Experience settings to "Display in Software Center, and only show notifications for computer restarts".

If you have a lot of applications already deployed, going through them one by one would be quite a chore. But, you can easily change all their settings via PowerShell.

In the code below, it changes the settings for every application we have deployed to the "User Optional - Software Center" collection.

#Import ConfigMgr PS module
Import-Module "$env:SMS_ADMIN_UI_PATH\..\configurationmanager.psd1"

#Connect to ConfigMgr drive
$SiteCode = Get-PSDrive -PSProvider CMSITE
Push-Location "$($SiteCode.Name):\"

#Change User Experience
Get-CMApplicationDeployment | Where-Object { 
    $_.CollectionName -eq 'User Optional - Software Center' 
} | Set-CMApplicationDeployment -UserNotification DisplaySoftwareCenterOnly

H/T Reddit