[JOINDER AGREEMENT This Consortium Agreement” IDG” Senior Management Members Reference is hereby made to the Consortium Agreement dated May 18, 2015 (the “ CBC Schedule A In addition, each of the other Parties to the Consortium Agreement hereby agrees to amend and restate (1) Name of Party (2) Number of Ordinary Shares Rolled (3) Number of Ordinary Shares Not Rolled] [EQUITY CONTRIBUTION AND VOTING AGREEMENT Agreement Parent Company Schedule A Rollover Shareholder Rollover Shareholders EQUITY CONTRIBUTION AND VOTING AGREEMENT (this “ RECITALS Merger Sub Merger Agreement Merger WHEREAS, concurrently herewith, Parent, SUNFLOWER MERGER SUB LIMITED, an exempted company with limited liability incorporated under the laws of the Cayman Islands and a wholly owned subsidiary of Parent (“ Exchange Act Shares] [CHINA MERCHANTS BANK CO., LTD., NEW YORK BRANCH 535 Madison Ave., 18th Floor New York, NY 10022 CONFIDENTIAL June 5, 2015 Sunflower Merger Sub Limited Floor 17, Tower A China International Center No. 33 Zhongshan 3rd Road Yuexiu District Guangzhou 510055 People’s Republic of China Attention: Mr. Yuqiang Deng Project Sunflower Commitment Letter Ladies and Gentlemen: CMB NY we us] [CUSIP No. 86737M 100 1. Name of reporting person. Yuqiang Deng 2. Check the appropriate box if a member of a group (see instructions) x ¨ (a) 3. SEC use only 4. Source of funds (see instructions) OO – See Item 3 5. ¨ 6. Citizenship or place of organization People’s Republic of China]

[I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY) IGG Inc. IRS No. 00-0000000 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* o (a) o (b) 3 SEC USE ONLY 4 SOURCE OF FUNDS (See Instructions) WC 5 ¨ 6 CITIZENSHIP OR PLACE OF ORGANIZATION NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON]

[CONSORTIUM AGREEMENT among THE PARTIES NAMED IN SCHEDULE A HERETO, IDG-ACCEL CHINA GROWTH FUND L.P., IDG-ACCEL CHINA GROWTH FUND-A L.P., IDG TECHNOLOGY VENTURE INVESTMENT III, L.P. and IDG-ACCEL CHINA INVESTORS L.P. Dated as of May 18, 2015 TABLE OF CONTENTS Page ARTICLE I PROPOSAL; DEBT FINANCING; HOLDCO OWNERSHIP 1 Section 1.01 Transaction 1 Section 1.02 Additional Consortium Members 1 Section] [CUSIP No. 86737M 100 1. Name of reporting person. Yuqiang Deng 2. Check the appropriate box if a member of a group (see instructions) x ¨ (a) 3. SEC use only 4. Source of funds (see instructions) OO – See Item 3 5. ¨ 6. Citizenship or place of organization People’s Republic of China Number of]