Several phases to DevOps maturity are as follows:-Waterfall DevelopmentBefore continuous integration, development teams would write a bunch of code for three to four months. Then those teams would merge their code in order to release it. The different versions of code would be so different and have so many changes that the actual integration step could take months. This process was very unproductive.Continuous IntegrationContinuous integration is the practice of quickly integrating newly developed code with the main body of code that is to be released, thus saving a lot of time when the team is ready to release the code.Automation is required to successfully execute continuous integration. Continuous integration is often the first step down the path toward DevOps maturity.Continuous integration process from a DevOps perspective involves checking your code in, compiling it into usable (often binary executable) code and running some basic validation testing.Continuous DeliveryContinuous delivery is an extension of continuous integration.When executing continuous delivery, you add additional automation and testing so that you don’t just merge the code with the main code line frequently, but you get the code nearly ready to deploy with almost no human intervention.It’s the practice of having the code base continuously in a ready-to-deploy state.Continuous DeploymentContinuous deployment, not to be confused with continuous delivery, is a practice of deploying all the way into production without any human intervention.Teams that utilize continuous delivery don’t deploy untested code; instead, newly created code runs through automated testing before it gets pushed out to production. There’s an automated feedback loop that monitors quality and usage before the code is propagated further.