Last week's release of the Windows 10 Insider Preview for phone build 10080 to members on the Fast ring update schedule won't likely be replicated to Windows Insider members on the Slow ring.
According to a Twitter message from Windows Insider member Gabriel Aul:
"10080 isn't likely to go to Slow ring because of a few issues being reported. Will look to next build as candidate for Slow."
Fast ring members of the Windows Insider program get updates to Windows 10 for PCs and phones immediately, but also have to deal with more bugs. Slow ring members don't get updates as quickly but those build should be more stable.
Microsoft added a ton of new features for the 10080 phone build update, including the revamped Windows Phone Store in beta form, support for the new Xbox and Office apps and more. However, the company launched the build with a long list of known issues as well for members on the Fast ring update.
Source: Gabriel Aul (Twitter)