Topics to cover for software developer interested in data analytics
Welcome to the community!! There can be a lot of answers to this question but I would suggest you the approach I took when I shifted from software development to the data science field.

1) Refresh your statistics and probability concepts. You should not go into too much details but you must understand basic things like Gaussian Distribution, Mean, Variance, Probability,etc.

2) Go through the basics of Machine Learning concepts. I prefer Andrew Ng's machine learning course on Coursera. That will help you build a strong foundation and will give you a great start in the field

3) Choose a particular language Python/R for building models. Though it's totally upto you but I prefer python as it has great libraries for machine learning as well as Deep learning.

4) Take part in competitions. We learn by doing not by taking only lectures. I suggest you should join Kaggle and the slack community out there namely, 'KaggleNoobs'. It's a great community. I learn everyday a new thing from there.

P.S: Data Science is a vast field. It demands from you various skill set like Data Analysis, Data Visualisation, Machine Learning,etc. So sometimes it can become frustrating too. But once you start enjoying it, you will become a master eventually.