To use this module:

1.  Go to **Invoicing \> Customers \> Customer Contracts** if you are a
    billing user.
2.  Select as many contracts as you want to update line prices.
3.  Click on Action button and execute the wizard **Create revision of
    contract lines**.
4.  Enter date start from which the new price will be valid and enter
    date end and percentage to increase old contract lines.
5.  By clicking on Apply button, a new contract line will be created
    with a price increased accordingly to the percent entered. Old
    contract lines will have as ending date the day before the entered
    date.
6.  When create invoices related to contracts selected, prices will be
    update with the prices that are not out of date.
7.  When managing contract with recurrence on line level, you maybe want
    not to revise price for some lines. Check 'Never Revise Price' on
    line level to avoid price revisions.