[Beta]

One comment about converting older adventures for use in CRB: I've never really had much trouble, so long as I took a pretty generic view.  That is, I didn't worry about the exact numbers from previous editions, but the basic ware and gear and spells haven't changed that much, so whatever the numbers an Ares Predator is an Ares Predator, Wired Reflexes are Wired Reflexes, etc.  And archetypes also often bridge editions (gangers, security guards, combat mages, etc), so I'd just grab PC or NPC archetypes from the 5e CRB, maybe tweaking to the appropriate experience level (I tend to work at dice pool level with most NPC anyway).

I did find it important to get a feel for typical attribute levels and adjust that a bit by edition (for example, in 2e a starting character could have 5 in all attributes while in 6e the highest is an average of 4 in all attributes), so lowering attributes in some cases to make resistances more appropriate.

[MercilessMing]

Same, I barely stat my NPCs anyway (one or two dicepools is usually enough to define minor characters) so I treat the old adventures much like the new ones are written: a collection of story beats.  I had fun converting Dreamchipper to a street level campaign.  It makes for a nice transition adventure when the runners are ready to move on to bigger things - set it up early so their mentor NPCs in the early campaign are the runner team they have to hunt down.  It's beautiful.

[Sir Ludwig]

I have never had an issue running older adventure in the current setting.  The two last games I ran (new players) was Mercurial and Queen Euphoria for 6th.  Like already said, you mainly just need an idea of what the NPS is up too.  The rest can be status found in existing books. 

SL