Attack Flow 2.1.0

This release of Attack Flow includes some highly requested features as well as a slew of under-the-hood improvements.

• Splash screen: improve user experience by showing a splash screen.
• Autocomplete: fill in ATT&CK tactics and techniques with autocompletion of TIDs or keywords.
• Recover unsaved work: if you close a tab, hit back, reload, etc. without saving changes, you now have the option to recover flows that were edited but not saved.
• Search in flow: navigate large flows quickly by searching for text that appears anywhere in the flow.

The Attack Flow format is unchanged in this release. It is backward compatible with all 2.0.0 flows. Note that the Attack Flow Builder has stricter validation rules, and some pre-existing flows may have new validation errors appear when you open this. This is normal and expected.