Hi!
This will be an option in the future, but not yet in developpement (as today, is using language strings by default to be multi-langual.)
Today, you need to edit code to allow this. But if you edit code, after each update, you will have to edit it again.
So,
Just edit the file ROOT/administrator/components/com_icagenda/config.xml
Replace this (around line 606) :
name="emailUserBodyPeriod"
type="textarea"
by this :
name="emailUserBodyPeriod"
type="editor"
And replace this (around line 628) :
name="emailUserBodyDate"
type="textarea"
by this :
name="emailUserBodyDate"
type="editor"
Then, in file ROOT/components/com_icagenda/helpers/icmodel.php
Add this :
$mailer->isHTML(true);
$mailer->Encoding = 'base64';
around line 4115, to have something like this :
// Set Body of USER and ADMIN email
$mailer->isHTML(true);
$mailer->Encoding = 'base64';
$mailer->setBody($body);
$adminmailer->setBody($adminbody);
It should give you possibility to send html email.
Best Regards,
Cyril