OTM (Oracle Transportation Management) upgrading has its own challenges and risks. Thus, a major upgrade or major version increase will typically take more than six months or so. You should have standard risk mitigation action plans. The major risks from upgrades comes from both internal and external factors. These are some common ones that you can take note.
Know your Application
Upgrade errors usually comes from customisation that are done to the product. Such errors usually need product team to analyse the root cause and provide a resolution plan. You should always remove or isolate customisation prior to upgrades as part of your risk mitigation plan. Another risk comes from the potential changes to your customised modules. It is advisable to develop configurable settings instead of hardcoding them to your application.
Know your Architecture
OTM upgrading impact for on premise is a much difficult than managing on the Cloud. This is because your infrastructure is likely non configurable and needs to be manually changed one by one. The complexity setup of your OTM architecture should be prepared prior to upgrading to lower the risks. This makes you aware of the firewall or SSL certs to be deployed when you conduct the upgrading.
The common risks for OTM upgrading is customised features and architecture setup. Customisation impacts patches or upgrading scripts. This often leads to specific architecture requirements and firewall with your on premise applications. Although these risks are not new, they are time consuming and impact the upgrading duration. Thus, you should always be proactive to mitigate the risks.