What should developers be learning now to be ready for the future?

The languages, tools, and technologies that we use as developers are always changing. What should developers be learning now to be ready for the future?

I can't tell what should developers be learning now to be ready for the future, there is no answer for this question.

We need to diversity our knowledge portfolio. As a developer, we would invest regularly in our knowledge portfolio. There are several ways to catch up with or keep in front of the technologies for the future.  Such as,

• learn at least one new language every year, 
• read a technical book frequently (for instance:each quarter), 
• read non-technical books as well(reading always help in both technique and non-technique), 
• participate in local user groups (keep in touch with friends and make new friends in technique field), 
• experiment with different environments (don't just only work with MS Windows, UNIX or IOS), 
• stay current (be curious with new stuff), 
• get wired (internet is a powerful tool, Google is a good friend!). 

And finally, keep review and re-balance, we can't learn everything.