In this guide 6 sections
Fix your billing software when its source or database is accessible and its data model can hold a state and an HSN code. Replace it when the source is gone, the model has no place for those fields, or the vendor cannot be reached. GullySystem decides after reviewing three months of real invoices with your accountant.
Start with real invoices, not a description
Pull three months of actual invoices, credit notes and challans. Sit with your accountant and list every kind of supply you make.
Local sales, interstate sales, branch transfers, job work, exports and reverse charge purchases may all appear. Each one is a set of rules the software must follow. The list tells you how much the software must do.
When fixing around the old software works
Reasonably built software can often be extended. Tax decided by place of supply, validation, portal links and Tally posting can sit around what already runs.
Staff keep screens they know. Training stays small.
- Source code or database you can reach
- Customer addresses with state as a real field
- Items that can carry an HSN or SAC code
- A vendor or developer you can still contact
When replacement becomes the route
Some software cannot be fixed safely. The source is lost, or the vendor has closed, or state lives in a free-text address line.
Patching a model like that means guessing at every invoice. Replacement costs more upfront but stops the guessing.
Whichever way you go, plan a period of parallel billing. Raise real invoices both ways and compare the registers before switching.
- No access to source or database
- No field for state or HSN in the data model
- A vendor who no longer answers
Clean the masters before either path
Most invoicing errors start in the item and party masters. Items without HSN codes, GSTINs that fail their check and addresses with no state field cause trouble in any software.
Clean them first. Only someone from your product team can say what an unclassified item really is, so plan for their time.
When neither is needed
A single-counter shop billing locally, with an accountant comfortable in Tally, may not need custom invoicing work. Cleaning the item master and fixing the print format can be the whole job.
The same holds where accounts are in order and the CA has no open issues. Spending on new software then adds cost without adding value.
Fix-or-replace scorecard
List your transaction types down one side and your current software’s gaps across the top. Tick each gap that blocks a transaction type. A few ticks suggest fixing; ticks across most rows suggest replacing.
Open a blank worksheet to printQuestions owners ask
Will we have to replace Tally as well?
No. Tally can stay where the books and the accountant live. The billing system raises documents and posts entries into the right ledgers.
Does new billing software make our invoices compliant by itself?
No. Software applies the treatment your accountant has agreed in writing. The compliance opinion, and filing, stay with your CA.
Can we fix the software before e-invoicing applies to us?
Yes. Your CA can tell you when you are likely to cross the notified limit. Building the portal link before then avoids a rush.