if you upgrading to a newer version you can get some new features in comparison to an older version.in software world every day you can get new features in the operating system for use of those features you also upgrade your software.
if you are using older operating system then you can't use latest version software with an older version of an operating system.or if you using latest operating system then you can use older version software but you can't get a new feature in it so as per conclusion if you want to use the new feature of a software then you have to upgrade your system too.
in brief, i want to say one more thing is that if you use the latest system then you can't use an older version of it by its configuration dependency.
in time of 2 months of register with QuickBooks, you can upgrade your QuickBooks software from its official site.
upgrading your QuickBooks software are two type:-
1 is you can install both versions of it without deleting existing version
2 is you can upgrade it and delete older version from a system.
so it depends on you what you want to make a separate copy of both or a single upgrade version.
Upgrading Company files
for upgrading company file is simple you have to open company file to your latest version QuickBooks Software.but before that you have to know
that you have to make a copy of company file in another folder for data saving. because after upgrading company file you have to check any error in company file comes or not.
if did not get any error then you can delete company data file.
if you get an error in company file then you have a copy to solve that issues otherwise you can be lost data and for recover data, you have to spend much more money.
for more information or solution you can dial QuickBooks Customer Service