One of the (legal ?) requirements we had to meet back in the 00s was that financial software (quant code, options trading) was "reproducible" for some length of time (7 years?). That meant: version control (SCCS, CVS, svn), archiving OS versions (SunOS, Solaris), and kit (Sun workstations and servers).

I have no idea if the last 2 ("OS", hardware) is even achievable in 2021. I can always get my source code from git, and possibly the 'configuration', but can I expect to run cloudy code in 7 years time?