I have updated / I want to change my rates. What will happen / how do I do it?
This means your historic time entries will not be affected: all historic calculations will be carried out using the old rates, and you can still see the old rates when you zoom in to the individual time entries.
In some scenarios, you DO want to change historic activity / rates: you may have been a few days late logging a rate change, or a mistake may have caused an entire project to be logged with erroneous rates.
In that case, an admin user can go to Reporting > Logbook and use the bulk actions to bulk reassign rates, or update rates to reflect the current rate. Simply filter to get the appropriate data set, check the time entries you'd like to change, and select "Change or update activity/rate".