Microsoft Skype for Business for iOS and Android mobile clients can't show the display name of a federated contact in the contact list. Additionally, users may see only the SIP address displayed in there. It's expected that the mobile clients can show the display names exactly like the Skype for Business 2015 (Lync 2013) or Skype for Business 2016 desktop client for the federated contacts.
Notice: This website is an unofficial Microsoft Knowledge Base (hereinafter KB) archive and is intended to provide a reliable access to deleted content from Microsoft KB. All KB articles are owned by Microsoft Corporation. Read full disclaimer for more details.