Earlier today, Android Central caught word that the Epic and Zio would receive an over-the-air (OTA) update to Froyo on February 21, but had nothing more than copied and pasted text from the Sprint system. Fast forward a few hours, and we now have more concrete evidence in the form a screenshots from Sprint's internal system that confirm the update is coming:

epic_zio_froyo

The image is courtesy of XDA member bentiger, and confirms his earlier statement that there was a Sprint internal announcement that the updates were rolling out:

I just saw an official release from Sprint Dealer News.

Software Updates: Samsung Epic (EB13, Froyo) & Sanyo Zio (2.200SP, Froyo)
Effective 2/21/11, software updates will be available for both devices Over-the-Air (OTA). Both updates will be pushed over a period of days, so customers will receive them based on their status on the Google servers. Details:

Samsung Epic
Update will be pushed over a 4-day period
After the update completes, verify the new software version (Menu > Settings > About Phone)
Baseband Version = S: D700.0.5S.EB13
Build Number = FROYO.EB13
Enhancements/fixes: upgrade to Froyo 2.2, improved bluetooth device support, bluetooth voice dialing, Flash Player 10.1, GPS enhancements, improved OS performance, ability to install applications to external storage

Sanyo Zio
Updates will be pushed over a 5-day period
Customers are required to download (accept) three portions of the update to receive Froyo 2.2
Customers should use WiFi if possible to complete the update
After the updates complete, verify the new software version (Menu > Settings > About Phone)
Baseband Version = S.M910.04.5.DF05
Build Number = Samsung ÉCLAIR.DF05
Enhancements/fixes: upgrade to Froyo 2.2, addition of Swype, Sprint Zone 2.5.5, Sprint ID activation improvements, better battery life

He goes on to provide an internal Sprint PDF document with details on the update, including install instructions and a timeframe:

pdfss

I'd say this is confirmed, wouldn't you?

[Source: XDA-Developers 1, 2. Thanks for the tip (again), Chris!]