Changing software without breaking the series
When a client moves into the app, the new series must continue from the last number, not restart at 1 if the same series is still open. A gap or a duplicate is a problem for VeriFactu chaining. You set the next number. The app does not read the old program by itself.
Continue, do not go back to 1
If the series from the old program is still in use, the next number is the one that was due, not 1. Restarting creates a gap or a duplicate. Both break the chain of records.
- Continue from the last number.
- Do not restart at 1 if the series is still open.
- A gap or a duplicate breaks the chain.
You set the next number
You type the number when you set up the series. The app does not open the previous program to read the last one. How this meets VeriFactu is in VeriFactu for gestoría firms.
Common questions
Can I start the series at 1 when changing software?
No, if the same series is still open. It has to continue from the last number. A gap or a duplicate breaks the chain.
Does the app read the number from the old program?
No. You set the next number. The app does not read the old program by itself.
Official sources
Informational text reviewed on 26 September 2026. It is not tax advice and does not replace the Spanish Tax Agency or your accountant. Deadlines, rates, and forms can change.