On February 22, 2007, Google introduced Google Apps Premier Edition, which differed from the free version by offering more storage (10 GB per user), APIs for business integration, 99.9% uptime for Gmail, and 24/7 phone support. It cost $50 per user account per year. According to Google, early adopters of Google Apps Premier Edition included Procter & Gamble, San Francisco Bay Pediatrics, and Salesforce.com. Additionally, all editions of Google Apps were then able to use Google Documents and Spreadsheets, users could access Gmail on BlackBerry mobile devices, and administrators gained more application control. Further enhancements came, on June 25, 2007, when Google added a number of features to Google Apps, including mail migration from external IMAP servers, shared address books, a visual overhaul of Google Docs and Google Sheets, and increased Gmail attachment size. A ZDNet article noted that Google Apps now offered a tool for switching from the popular Exchange Server and Lotus Notes, positioning Google as an alternative to Microsoft and IBM. On October 3, 2007, a month after acquiring Postini, Google announced that the startup's email security and compliance options had been added to Google Apps Premier Edition. Customers now had the ability to better configure their spam and virus filtering, implement retention policies, restore deleted messages, and give administrators access to all emails.