You can update the default text on the buttons for all guides and all users.
we call this a tiplate (tip + template :-)). If you need this for supporting multiple languages please refer to this knowledge-base article.
If you want to update the text of the next button on a specific guide for all users you can do that using the setting 'Change Next button text to'. You will find it in the display setting in the Iridize editor.
If you want to change the text of the next button on a specific guide based on a certain user setting you can do that too.
First you will need to set an Iridize variable like so:
than you can set the 'change next button text' setting to:
and the button will then display 007 (instead of next)
To read more about personalization and customization options read this knowledge-base article.