Promotional text is the fast-moving field on an App Store product page. It appears above the description and lets you mention current features without shipping a new app version.
The limit
Apple's platform version reference caps promotional text at 170 characters. That is enough for one launch message, one seasonal hook, or one clear feature push. It is not enough for a second description.
Good uses
- Announce a new feature after release approval.
- Match a paid campaign with the same wording.
- Swap seasonal copy without touching screenshots.
Bad uses
Avoid time-sensitive promises you will forget to remove. Avoid pricing, ranking, and "best app" style claims unless they are current, accurate, and allowed by the store rules that apply to your listing.
Source notes
Apple documents promotional text under platform version information, including where it appears and the 170-character maximum.