Last week, the Fast Ring participants in the Windows Insider program received Build 10041 for testing. And, with it came a series of bugs which led to complaints. That's the pains of always wanting to be first in line, I guess.
Yesterday, while the Slow Ringers finally received this new build, a couple stability and reliability updates led the way to help bring Fast Ring Builds up to speed. Since the initial release, Microsoft has been working to solve the glaring issues and the updates solve those. Slow Ring users won't need the update since those fixes are already built in.
Additionally, late yesterday afternoon, Microsoft also delivered the ISOs for the Build. The ISOs are great for testers who want to install a clean operating environment on multiple computers.
You can grab the latest ISO here: Download Windows 10 Technical Preview ISO March Update
Microsoft has promised to ISOs with each released Build, but this month, with the company also promising faster fast Builds, it shows that ISOs probably won't release until the Slow Ring offerings are available.