Failure Patterns, Migration and Official Sources
Switching payroll software mid-year: migration plan, year-to-date data and the parallel run
How to move payroll to new software in India without breaking TDS, PF or ESI: timing, the data to migrate, year-to-date balances, a parallel run and reconciliation steps.
You can switch payroll software in the middle of the financial year, but only if you carry over year-to-date (YTD) salary and TDS for every employee, keep PF, ESI, PT and LWF continuity, and run at least one month in parallel before you switch off the old system. The safest go-live points are quarter starts (1 April, 1 July, 1 October, 1 January), because the quarterly TDS return (Form 138 under the Income-tax Rules, 2026) then comes from one system. This guide sets out a step-by-step plan.
It belongs to the guide on why payroll software projects fail.
Choose the go-live date
| Go-live | Advantage | Watch out for |
|---|---|---|
| 1 April | Clean tax year; no YTD for TDS | Busy year-end; Form 130 for the old year still from the old system |
| 1 July / 1 October / 1 January | Quarterly TDS return from one system | YTD salary and TDS must be migrated |
| Mid-quarter | Fastest after a decision | Quarter's return combines two sources; highest risk |
For September 2026 specifically, the EPF ceiling change on 17 September split the month into two calculation periods; avoid migrating with that month as the first live month unless the new system handles the split.
Data to migrate
| Data | Detail | Check against |
|---|---|---|
| Employee master | Name, IDs, joining date, category, location, state, department, cost centre | HR files |
| Statutory IDs | UAN, ESI IP number, PAN, Aadhaar where lawfully held | EPFO, ESIC and e-filing records |
| Bank details | Account and IFSC | Bank validation |
| Salary structure | Components, code wages, 50% add-back, effective dates | Appointment letters, revisions |
| YTD earnings | Each component, April to last month | Old payroll register |
| YTD TDS | Tax deducted each month | Challans and Form 138 filed |
| YTD PF, ESI, PT, LWF | Contributions by month | ECR, ESI filings, PT returns |
| Tax regime and Form 124 | Choice and declared claims | Employee declarations |
| Previous employer data | For mid-year joiners (Form 127) | Employee submissions |
| Leave balances | Opening, accrued, availed | Leave records |
| Loans and advances | Outstanding balances and EMIs | Accounts |
| Gratuity service data | Continuous service, fixed-term contracts | HR files |
Get the data from the old vendor or bureau in a usable format. Your contract should require this; see contract and exit terms.
Step-by-step plan
- Freeze scope. Decide which modules go live first. Payroll and statutory first; performance and recruitment later.
- Clean masters. Fix UAN, ESI, PAN and bank mismatches before import.
- Configure rules. States, PT and LWF, ESI periods, EPF ceiling and voluntary PF policy, overtime, leave policies, bonus and gratuity settings.
- Import YTD. Import by component and month where possible, not just totals.
- Test five cases. The same five employee types as in the best-fit method.
- Parallel run. Run the full month in both systems.
- Reconcile. Compare every employee and every statutory total.
- Sign off. Owner, accounts and, if used, your CA approve.
- Go live. Switch bank file and filings to the new system.
- Archive. Export registers, payslips and returns from the old system for retention.
The parallel run reconciliation
| Item | Tolerance | If different |
|---|---|---|
| Gross pay per employee | ₹0 | Check structures, attendance, arrears |
| Code wages (PF base) | ₹0 | Check 50% rule settings |
| PF employee and employer | ₹0 (rounding rules aside) | Check ceiling, voluntary PF, EPS split |
| ESI | ₹0 | Check contribution-period continuation |
| PT and LWF | ₹0 | Check state and month settings |
| Monthly TDS | Explainable difference only | Check YTD import, regime, declarations |
| Net pay | ₹0 | Trace to the above |
| Bank file total | Equals net pay total | Do not go live until equal |
TDS can legitimately differ if the new system re-projects the year more accurately; document the reason and agree how to handle the change with affected employees.
Costs of migration (illustrative)
| Line | Illustrative cost |
|---|---|
| Vendor migration or onboarding fee | ₹0–₹50,000 depending on size and complexity |
| Data export fee from old vendor or bureau | ₹0–₹25,000 (check your contract) |
| Internal effort for cleaning and parallel run | 30–80 hours |
| Consultant review | Optional, by engagement |
Include all of these in the one-time cost in the payback calculator.
Communicating with employees
- Tell employees when the payslip format and app will change.
- Ask them to check bank details, tax regime choice and declarations in the new self-service portal.
- Explain any TDS re-projection.
- Keep old payslips available for download.
Frequently asked questions
Can we migrate only totals for YTD?
You can, but monthly component-level data makes registers, arrears and reconciliation far easier. Totals are the minimum.
Who files Form 130 if we switch mid-year?
The employer files and issues it; your new system should produce it using migrated YTD data. Check that Form 138 data for earlier quarters is consistent.
How many parallel months do we need?
At least one; two if you have shifts, overtime or several states.
What if the old vendor will not give us our data?
Check your contract and request it in writing; in future, write data return into the contract before signing.
Sources
- Income Tax Department — Forms 124, 127, 130 and 138
- EPFO — UAN, ECR and ceiling changes
- ESIC — ESI contribution periods
- TRACES — TDS statement records
