You may modify receiving incoming calls from
your contacts only in profile page - setting
- privacy - call in new version.
Tips:
1. imo number is hidden by default except
account owner.
2. You may modify privacy setting in Profile
page - Settings - Privacy.
3. To secure your imo account, please do not
log on unknown device, click malicious links,
let out the verification code, phone number nor
private part of your body (avoid being recorded).