I just wanted to know if it will be possible to change a new form in the server after submitting some data. So after starting data collection I noticed a breach of both assertions assertions in two questions and I've just adjusted it now I'm going to load a new form at the odk aggregate server. My concern is how to proceed so as not to lose the data that was submitted before.
thank you so much
You can add small changes like changing text in labels constraints or something like that and the you can upload your form again. However adding bigger change like new questions/removing questions would require uploading a completly new/separate form.
The documentation page at https://docs.getodk.org/form-update/ expands on @Grzesiek2010's answer regarding form definition updates in Aggregate.
ODK's newer server, Central, allows more significant updates to form definitions and provides a process for testing those changes. For those using Central, see https://docs.getodk.org/central-forms/#central-forms-updates.