**The minimum PHP version required to run Arcanist is now PHP 5.5**, which was released seven years ago in 2013. Requiring this version of PHP allows Arcanist to use a few new language features, including: traits; `yield`; and `finally`. See T11968 for some details.
These flags to `arc` workflows have been removed:
| **arc diff** | `--plan-changes` | {icon times color=red} Removed, see T13010. Try `--draft`.
|---|
| | `--preview` | {icon times color=red} Removed, see T13010. Try `--draft`.
| | `--no-diff` | {icon times color=red} Removed, see T13010. Legacy flag.
| | `--cache` | {icon times color=red} Removed, see T13010. Legacy flag.
| **arc lint** | `--only-changed` | {icon times color=red} Removed. Try "warning" severity.
|---|
| | `--only-new` | {icon times color=red} Removed. Almost never worked correctly.
| | `--cache` | {icon times color=red} Removed. Legacy flag.