A new substitution in CBSubs

To use in the workflow e-mails in CBSubs there are theese substitutions amongst others: [SUBSCRIPTION_VALIDITY_PERIOD] and [SUBSCRIPTION_EXPIRY_DATE] - i really need also dynamically to show the start date of a plan period in mails (I have plans that last a calendar year). So something like [SUBSCRIPTION_VALIDITY_PERIOD_START] would be nice.. is that possible to add ?

Only way to use CBSubs substitutions outside those specific locations is to use the functionality included by CBSubs system plugin. It adds support for CBSubs substitutions anywhere Joomla content plugins are supported. So for whatever email you're sending you'll need to first enable support for content plugins. Next you can use the below format to get expiration date for example.

[cbsubs:subscriptions plan="PLAN_ID_HERE" output="expiry_date" /]

Replace PLAN_ID_HERE with the ID of your plan. See the description of the "cbpaidsubsbot" system plugin in Extensions > Plugins for further usage information for this content plugin.

I think I have not expressed my problem correct. I do not want to use substitutions in other places, I am asking for a new substitution variable.

I believe [SUBSCRIPTION_VALIDITY_PERIOD_START] would just be the value of [SUBSCRIPTION_SIGNUP_DATE], which should be the date they subscribed on.

But if the start date of the plan is eg the 1. of april, would that then be shown if they first sign up eg on the 5. of april ? I want to show 1. of april regardles of the actual signup date, but i want it also to change if the period later on is changed in the plan.

It should be set to whenever the subscription started. In the _cbsubs_subscriptions database table it'd be the value of subscription_date column, [SUBSCRIPTION_LAST_RENEWAL_DATE] would be the value of last_renewed_date column, and [SUBSCRIPTION_EXPIRY_DATE] would be the value of expiry_date column. There isn't much more information to go off of here. [SUBSCRIPTION_VALIDITY_PERIOD] for example is a calculation based off their subscription_date and expiry_date and the subscribed plans validity period.