Sitecore Upgrade - Codebase Upgrade Series

One of the task in a Sitecore upgrade project is to upgrade the codebase to be compatible with the target Sitecore version. I have listed some of the steps which I learnt and it helped me to upgrade the solution quickly. 

1. Remove unused references and nuget packages
2. Framework upgrade - .NET
3. Migrate to SDK Project Format (optional)
4. Migrate from packages.config to PackageReference
5. Replace Sitecore assemblies reference with nuget package
6. Upgrade Sitecore nuget packages
7. Upgrade .NET related nuget packages
8. Upgrade 3rd party nuget packages
9. Compile, replace obsolete methods and fix errors

Before upgrading the codebase, make sure to create a separate branch so that it does not affect the ongoing development tasks. 

Visual Studio PowerShell related articles to run scripts. 

- Visual Studio - PowerShell Package Manager Console Reload Profile Script

- Update .NET Version in SDK and Legacy Project Format Type

Sitecore Upgrade related articles.

- Sitecore Upgrade - Transfer Sitecore Membership User/Roles and Password

- Sitecore Upgrade - Transferred Sitecore Membership User Password does not work - Possible Reasons

- Sitecore Upgrade - Redis Session State crashes IIS App Pool