**The main new feature in this release is that Uproot 4 can now write ROOT files.** It is no longer necessary to use Uproot 3 for anything: Uproot 4's capabilities exceed Uproot 3's in all ways that are currently known to me.
This was implemented in PRs 405, 406, 408, 409, 412, 414, 415, 416, 420, 421, and was described in Discussion 321. All the new functions are documented, and an overview is presented in the [Getting Started Guide](https://uproot.readthedocs.io/en/latest/basic.html#opening-a-file-for-writing).
Other updates for this release:
* jpivarski removed warning when XRootD is installed but not used: PR 388.
* chrisburr allowed XRootD version strings to be non-numeric (e.g. from a self-built copy of the library): PR 395.
* bnavigator marked test 0220 with the network tag, since it uses the network: PR 396.
* jpivarski handled dimensions in a leaf-list: 399.
* jpivarski removed '' fields from lazy Forms, fixing lazy TLorentzVector: PR 403.
* klieret fixed links to source in Sphinx: PR 410.
* jpivarski allowed Float16_t to have up to 32 bits: PR 411.
* veprbl added support for reading TDatime: PR 407.