This is a major breaking release of the Solidity language and compiler that includes many new safety features. In general, programmers have to be more explicit, some weird edge-cases are removed from the language and the low-level compiler interface is much simpler.
This release was long overdue and as a result has amassed an incredibly long list of changes. Please refer to the "Solidity v0.5.0 Breaking Changes” section in the documentation about a good description of what has changed and how to update your code, or if you are courageous, check out the changelog!
A big thank you to all contributors who helped make this release possible!
Download the new version of Solidity here.