1. A method for updating user data by a task server based on a completion status of a combination of business task and conversation task to improve security of updating the user data, the task server comprising one or more processors and a non-transitory computer-readable storage medium, comprising: providing, by the task server, a task group including a plurality of tasks for a first user to complete; obtaining, by the task server, business flow data and conversation flow data of the first user; determining, by the task server, whether the first user has completed a preset first business task according to the obtained business flow data, and whether the first user has completed a preset first conversation task according to the obtained conversation flow data; and in response to determining the completion status of the combination of the preset first business task and preset first conversation task, and a difference between a moment to complete the preset first business task and a moment to complete the preset first conversation task is less than a second threshold value, obtaining, by the task server, a user data update volume corresponding to a first task group according to a mapping relationship between the task group and the user data update volume, and updating, by the task server, the user data corresponding to the first user according to the user data update volume corresponding to the first task group, such that the security of updating the user data is improved, wherein the first task group comprises the first business task and the first conversation task.