I am also curious about this, I recently had to do a fresh install because the upgrade script from nc 12 to 14 was useless and my service provider updated the php configuration.
I basically just use nextcloud for contacts, sms backup and calendars. Seems strange that there is no easy export feature for the calendar and contacts. Tried to use the vcf export but the nc 12 creates a corrupt file so that didnt work. Tried to export calendars but I just got some garbled empty file that took ages to import and nothing there.
To be honest, this is garbage. No working upgrade feature and no working export/import? I mean, would love to continue using this product but if this is what I can expect of it in the future my use of it probably ends here, most certainly wont pay for any enterprise upgrade. Even the simple update from 14.04 to 14.06 on a fresh install garbled it, probably have to do a new fresh install now. Seems like a simple thing to get right if you know what you’re doing but doesn’t seem like administrating this software is something that is meant for normal people. Maybe the errors are created to sell expensive enterprise support. Who knows. I know nextcloud is going out the window and going back to owncloud.
Really disappointed with nc and really regret switching from owncloud now.