SIGNATURES OF REPORTING PERSONS This Statement on Form 4 is filed by the Reporting Persons listed below. Dated: July 5, 2018 SILVER PRIVATE HOLDINGS I, LLC By: Silver Private Investments, LLC, its sole member By: /s/ Peter Berger ---------------------------------- Name: Peter Berger Title: Authorized Signatory SILVER PRIVATE INVESTMENTS, LLC By: /s/ Peter Berger ---------------------------------- Name: Peter Berger Title: Authorized Signatory SIRIS PARTNERS III, L.P. SIRIS PARTNERS III PARALLEL, L.P. By: Siris Partners GP III, L.P., its general partner By: Siris GP HoldCo III, LLC, its general partner By: /s/ Peter Berger ---------------------------------- Name: Peter Berger Title: Managing Member SIRIS PARTNERS GP III, L.P. By: Siris GP HoldCo III, LLC, its general partner By: /s/ Peter Berger ---------------------------------- Name: Peter Berger Title: Managing Member SIRIS GP HOLDCO III, LLC By: /s/ Peter Berger ---------------------------------- Name: Peter Berger Title: Managing Member SIRIS CAPITAL GROUP III, L.P. By: Siris Advisor HoldCo III, LLC, its general partner By: /s/ Peter Berger ---------------------------------- Name: Peter Berger Title: Managing Member SIRIS CAPITAL GROUP, LLC By: Siris Advisor HoldCo, LLC, its managing member By: /s/ Peter Berger ---------------------------------- Name: Peter Berger Title: Managing Member SIRIS ADVISOR HOLDCO III, LLC By: /s/ Peter Berger ---------------------------------- Name: Peter Berger Title: Managing Member SIRIS ADVISOR HOLDCO, LLC By: /s/ Peter Berger ---------------------------------- Name: Peter Berger Title: Managing Member