Slack users who don’t want their chat history and files to be deleted will have to pay for it, the company has announced. The corporate chat platform says it will begin deleting messages and files older than a year from free workspaces from August 26 onwards – unless the users subscribe to a paid plan. In June users began receiving emails from Slack that “free workspace content older than one year will be deleted.” Free users will also only have access to the past 90 days of messages and files, Slack says in a new help page for free customers. To access the remaining 275 days of stored data, a…