BlueMail supports GAL (Global Address List) for Exchange.
GAL is integrated into our Auto-Complete feature. When composing an email, simply begin typing the recipient's email address into the To field and our Auto-Complete/GAL feature will kick in. BlueMail suggests relevant addresses from the people you have emailed, from your device's own address book, and from the contacts held by Google, Outlook and Microsoft 365 accounts you signed in to through the provider's sign-in page. If your account is an Exchange ActiveSync account that supports GAL, your GAL addresses appear as well — see Does BlueMail integrate with my Provider/Device Contacts?.
