You can uninstall any versions for which you no longer have active files (once you have confirmed that any upgraded files were transferred successfully).  I like to keep one or two older versions so that I can have, e.g., 3 company files open at once.

Resolution for '2015 versions issue: 'May I uninstall older versions of QuickBooks Pro on my computer. I currently run 2016. May I delete 2012, 2013, 2014, 2015 versions?' available: Yes.

The 2015 versions issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the 2015 versions issue yourself by looking for a resolution described in the article. If it is a complex 2015 versions issue or you are unable to solve the issue, you may contact us by clicking here or by using other 2015 versions support options.

For more information about resolving issues related to 2015 versions in Quickbooks/QBO or to get support for the issue 'May I uninstall older versions of QuickBooks Pro on my computer. I currently run 2016. May I delete 2012, 2013, 2014, 2015 versions?', click the link below: