Switching from legacy housing software without breaking your rent run

Most of our new customers are coming off a housing system that's been running since the mid-2000s. The fear isn't change — it's the rent run. Miss a week of rent postings and you've got a difficult month. This playbook is what we use with customers to make sure that doesn't happen.

Sequence the work, don't collapse it

A migration is five streams running in parallel:

1. Discovery. Inventory every field, every integration, every workaround.
2. Data. Extract, clean, map, load — and iterate at least three times.
3. Configuration. Rent schemes, service charges, workflows, user roles.
4. Integrations. Payments, document management, contractor portals, BI.
5. People. Training, champions, comms, confidence.

Cutover is the moment all five are finally good enough at the same time. If you're compressing any one of these streams to hit a date, you're borrowing risk from the weekend itself. Don't.

The data is the project

Housing data is messy because housing is messy. Tenancies that were never properly ended, rent schemes that've been superseded three times, service charge reconciliations sitting in a shared drive. The migration is an opportunity to clean it up — but only if you plan for the cleaning.

Expect three data loads:

• Load 1: ugly. Shows you what's in the data.
• Load 2: cleaner. Agree what to fix at source vs in transit.
• Load 3: the dress rehearsal. This one has to be good enough to go live with.

Do not attempt to go live on load 2. The dress rehearsal is non-negotiable — it's where you rehearse the rent run on the new system with last week's actual data.

The cutover weekend

Pick a weekend where there's no bank holiday, no rent scheme change, and no payroll run. Typically a Friday-to-Monday window with:

• Friday evening: final extract from legacy, data freeze.
• Saturday: load, reconcile, integration smoke tests.
• Sunday: user acceptance on the new system, sign-off gate.
• Monday morning: live — with the implementation lead on a call from 7:30am.

Have a documented rollback plan. You will (almost certainly) not use it. You will absolutely need to know it exists.

The rent run is the one thing

The first rent run on the new system is the only moment that matters. Everything else can have a workaround for a week. If the rent run fails, you've got arrears letters going out that shouldn't, direct debits missing, and a finance team with a very bad Monday.

Protect it like this:

• Run parallel rent runs on both systems for two full cycles before cutover.
• Reconcile to the penny. Any variance is investigated, not explained away.
• On go-live Monday, the implementation lead runs the rent cycle shoulder-to-shoulder with your finance lead.

Things that catch teams out

• Contractor integrations. Everyone forgets about the repairs portal until the Wednesday before go-live.
• Document management. The tenancy file on the old system has PDFs, emails, hand-written notes. Plan the migration, don't assume it.
• Email templates. Letter templates embed old field names and old logos. Factor in redesign time.
• Reports that no-one writes down. A board report someone builds from a saved query every quarter is the thing that breaks on day 1.
• The quiet team. The one user who's been on the old system for 15 years and hasn't said a word. Find them, include them, listen.

What “good” looks like after go-live

Two weeks after go-live the team should be frustrated with new things — reports they want, workflows they want tweaked — not panicked about old things. Three months in, the old system should be read-only and scheduled for decommission. Six months in, the conversation should be about what the new tooling lets you do that the old one never did.

How we approach this at CHICS

We've done this migration many times, from many different housing systems. We always run the two-cycle parallel rent run. We always do three data loads. We always have the implementation lead on the phone for go-live Monday. If any supplier tells you they can do it faster, ask what they're skipping.