I would expect the 2019 version to open and convert/update the 2015 file.
Resolution for '2019 version issue: 'Will Quickbooks Mac 2019 import data from 2015 version ?' available: Yes.
The 2019 version 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 2019 version issue yourself by looking for a resolution described in the article. If it is a complex 2019 version issue or you are unable to solve the issue, you may contact us by clicking here or by using other 2019 version support options.
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