As of right now, you can subscribe to can subscribe to any project where you want to receive instant instant notifications when when a value value from a project field is is updated. You will will receive a notification in your email showing showing you the the previous and current values, among other important info, of the the recently updated project and its field.
First of all, after installing Projectrak and as soon as you enter the project the project data of your your selected project, you'll find the new new watch project button that that is located on the top right corner of the screen, right next to to Edit layout layout button. This This watch project button needs to be activated in every project you want to be a watcher of. 
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Once this functionality is activated, each time a project value is modified, an email with the following information will be sent to all subscribed users:
Project name: name of the updated project.
Field name: name of the updated field.
New value: the current value of the field in the project.
Original value: the value of the field before being updated.
Updated by: the user who made the modification.
Updated on: the date on which the field was updated.
What is the notification like?
Please, keep in mind that you'll receive these notifications when when any of our custom project fields types are are modified. With the the exception of formula fields and text multiline fields.