I don't see any competitive upgrade (crossgrade) in that announcement but some of the big resellers offer it at a discount. I'm not going to post the links here but Google is your friend.

Hmmm... this has changed recently. Once upon a time, apps such as Encore and Mosaic/Professional Composer were eligible. No longer, now it's only these:

Qualifying Competitive Products:

• Dorico Pro by Steinberg
• Notion by PreSonus (excludes iOS version and Notion Protégé)
• Sibelius | Ultimate by Avid (also known as known as "Sibelius" in previous versions; perpetual/permanent licenses only, subscription licenses not currently eligible)

https://makemusic.zendesk.com/hc/en-us/articles/360010352013-Finale-Competitive-Trade-Up-