LimeSurvey offer ability to do a survey in multiple times with one token. If the survey is not anonymous and Enable token-based response persistence? is set to yes. Then the previous answer are reloaded.
But if the survey have incremental question index, the index show only the question until the last question viewed.
Then if user goes to page 10, go back to page one, save the survey and close it. When he start again the survey, only the 1st page is shown on the incremental index.
With this plugin, after activation, when the user come back to update his answers, the last page seens is saved in the database. And this last page seens is put in the maxstep parameters.
The index shown is complete : it show really the index to the last page submitted.