[Koha] ?s re Koha on a Mac - server died

[Shelley & Kurt Kemperman]

I work in a small school library.  The school's computers run on an  
Apple server.  When we installed Koha, the tech used a separate Dell  
server with Linux and connected it to the library Mac.  The Dell  
server just died and I have some questions.

Our new IT guy found a link to download Koha to a Mac, but that is  
version 3.0 - we originally had version 2.9, but I know that Koha is  
up to 3.6 at this point.  Is it recommended to download to a Mac and  
if so, is there an updated version available?  We do not need the  
capability to connect to other libraries in a network, but I do use  
the z39.50 function to import MARC records.  So, first ?, should we go  
with the Mac download or install a new Linux server/computer?

Second ?, our Koha records were backed up using CrashPlan so hopefully  
we didn't lose anything.  When we re-download Koha (whether on a Mac  
or with Linux), I would love to use an updated version.  Are we going  
to have problems restoring the original data into an updated version?

Thanks for any info,
Shelley