I would like to use LimeSurvey as a collaboration form instead of a real survey and storing versions of interactions with customer.

So:
- customer fill for the first time the form (the survey) and, sending it, save the first answers as Version1;
- he can write comments in a final text field;
- I read the form, I made some changes and some observations and things to be changed, I send this update and LimeSurvey should mantain Version1 responses but add a new set of resposes, the Version2;
- customer should be able to see changes and my observations and answering integrating what he wrote in Version1, and what I adjusted in Version2.. after this there is a new Version3;
- and so on..

I should be able to see every Version of the survey in every moment.

Should I "duplicate" the previous answer? And send a new token to my customer? How I can do it easily? Better if not through backend!!

Thank you

I think it is probably possible to do this with some kind of workaround, but Limesurvey is not made for this. I don't think it will be simple to do what you want to do. There are probably better tools than Limesurvey for this type of work. Why did you decide to go with Limesurvey, a survey tool, for your approach?

Because I know hot to use LimeSurvey and I want to exploit it to accomplish this new task!
I searched a tool to do this, but I didn't find it! Do you know any tool?

Looking at the manual

Allow multiple responses or update responses with one token?: Default: No. If you activate this setting, participants will be able to return to their survey by clicking the invitation link, even if they have already submitted the survey. If the survey is anonymous or "Enable token-based response persistence" is set to NO, this will add a new response. If the survey is not anonymous and "Enable token-based response persistence" is Yes, the user will update the existing responses.

I would like a

the survey is not anonymous and "Enable token-based response persistence" is Yes BUT this will add a new response

Yes, it will add a new response, because this is what it does once a survey is filled completely.

It will only continue in the old survey, if this wasn't finished. You might be able to change the status of a response to not complete, then the respondents would probably jump back into the previous response, but the problem is they would jump to the end of the survey. As I said, it is probably possible, but with a lot of workarounds. Not ideal.

Really can not be done out of the box easily.

Some idea , out of the box
- Use token
- Use allow update
- Use TOKEN:USESLEFT to put some condition on some question, for example show only the last comment if use left it at 0.

Not out of the box
with not anonymous token
- At end of the first survey, create another one with :
1. Same answer
2. Same token
3. An hidden question 'STATE' for a specific code (using it after and in survey)
4. Send the email to the team
When team submit : do the same thing but with another code on equation question type (you know actuel situation of the survey with 'STATE' value.