I don't believe there are any Sage provided external tools for that.  I would suggest you involve an experienced partner who might be good at knowing what to look for.  A heavily customized environment would add yet another level of complexity.

Recognize that you will need to go through a few upgrade utilities as there is no direct 2016 -> 2023 single upgrade.   For example, you may need the 2018 upgrade, followed by the 2021 upgrade, followed by the 2023 upgrade.  In general, a given upgrade will support the upgraded to version plus the previous 2 versions.  At what point(s) you test is also a decision.

Sage 500 ERP had the following released versions as of this writing:

2016

2017

2018

2019

2021

2023

2024

The next planned release is 2026 which will likely arrive in the September/October 2025 time frame.  As each new version is released, Sage currently supports that new release plus 2 versions back.  So as of this writing, version 2024, 2023, and 2021 are currently supported (although 1099s may be supported for an additional release depending upon timings at Sage's discretion).

Also keep in mind that various SQL Server version upgrades may be involved.  A qualified partner can also help out with such planning also.

Hi Ana, 

because each install is made up of a unique set of modules and setup work flows; there is not a One-size, fits all template. The best practice for this effort is as follows:

Gather a stakeholder from each team that uses Sage 500 ERP, such as warehouse personnel, accounting staff, report writers and so on. Build a test plan based on the day to day workflows for each team. The goal is to represent a set of transaction scenarios to cover your critical processes and as many outlying processes as possible. Be sure to include any reports you run at period end and routinely. 

Since you have customizations, work with your Sage partner or third party developer, if you need assistance with scenarios to verify whether customizations are working.

Review your imports or any automated processes and include testing for those as well.

Schedule sufficient time for the testing effort and plan to repeat testing as issues are addressed.

Thanks Ramon - yup, we are indeed going through each of these versions in our upgrade process.  Appreciate the insight to 2026 release, too!