Arvados

I would like to bump this. We've been pinned to the same version of Singularity as long as I've been here (3c1de8915ddc274136786e35dd3fecd0495f5e84). Given the upstream release cadence that can't be good.

Are there known challenges upgrading to Singularity 4.x? Just reading the list of runtime changes, I can imagine one or two of them might affect us but they seem pretty modest to deal with.

I reached out to our main Singularity end user to see what their plans are.