Your original developer left.
We'll maintain your legacy system.
Is there a VB6, ASP Classic, .NET Framework, or Java system nobody dares to touch? We take over the source code, restore the build environment, set up regression tests, and handle bug fixes and hotfixes under an annual contract. No rewrite. No migration.
- No rewrites, no migrations
- Team coverage, even when someone is out
- Full return of code and docs
Your dedicated legacy maintenance team
- Undocumented code, taken overInventory the source, recover missing components, restore the build
- Bug fixes and hotfixesCode-level troubleshooting of production issues
- Regression testing and releasesEvery change is tested before delivery
- Knowledge base and monthly reportsSystem knowledge lives in documents, not in one person's head
Does your legacy system face these problems?
It still runs your daily operations, but no one can take responsibility for maintaining it.
The original developer left or retired
Only one person understood the system, and they left without any handover.
No documentation, no one dares to change it
Change one report field and the month-end close comes out wrong. Every change is a gamble.
The original vendor is gone
The contractor shut down or stopped taking work, and the source code sits on some old PC.
Sudden failures
Production goes down, no one can troubleshoot it, and rebooting is the only hope.
No budget for a rewrite
Rewrite quotes run into the hundreds of thousands of US dollars and two years of work, while the system still works.
No one with the legacy skills
Hiring a full-time engineer for one system doesn't pay off, and the right people are hard to find.
Legacy system takeover and maintenance
First we confirm we can handle it. Then we take long-term responsibility.
Takeover assessment
We inventory the source code, dependencies, licenses, and deployment environment, then deliver a risk assessment report.
- Verify the source matches production
- Rebuild from source
- Establish a regression test baseline
Annual maintenance contract
A fixed block of monthly hours, with engineers who know your system handling fixes and releases.
- Bug fixes and hotfixes
- Regression testing and code review
- Regular maintenance reports
Minor change requests
Changes to report fields, calculation rules, or screens draw on the hours included in your monthly fee first.
- Impact analysis before any change
- Beyond included hours, we quote first
- Documentation updated afterward
Legacy technologies we support
We only take on technologies we truly know, so takeover cost and fix times can be estimated up front.
Core stacks
Desktop and departmental tools
Mobile apps
Reporting
Case by case
"Case by case" technologies are accepted only after a takeover assessment confirms we have the right engineers.
How a legacy takeover works
We prove we can handle your system before you sign a maintenance contract.
- 1
Takeover assessment
2 days to 4 weeks · FreeWe inventory the source code, dependencies, licenses, and deployment environment, then deliver a risk report.
- 2
Build restoration
During assessmentWe rebuild a binary that matches production from source and establish a test baseline.
- 3
Annual contract
12 months minimumChoose a plan by monthly hours and response time. Scope and overage rates are written into the contract.
- 4
Ongoing maintenance
Monthly deliveryFix, test, review, release. We keep the knowledge base current and send a monthly report.
Legacy maintenance plans and pricing
Your monthly fee converts to engineering hours at US$123 per hour. Use them for fixes, changes, and required SDK updates, and roll unused hours into the next month. Engineers who know your system are on it, so nothing goes unattended when one of them is out.
Internal systems that change a few times a year and only occasionally have issues.
US$12,120 per year
- Covers 8 engineering hours/month
- Response within 2 business days
- 8 hours a day, 5 days a week
- Quarterly maintenance report
Business-critical systems with change requests every month.
US$36,840 per year
- Covers 25 engineering hours/month
- Response within 4 business hours
- 8 hours a day, 5 days a week
- Quarterly system risk review
Core systems where downtime stops production or orders.
US$92,160 per year
- Covers 62 engineering hours/month
- 1-hour response to P1 incidents
- 24/7 on-call, year-round
- Post-incident review reports
Takeover assessment and build restoration
The takeover assessment is always free. Codebase size determines which plans are available. Size = lines of custom code + stored procedures, excluding tool-generated code.
| Size | Lines of code | Available plans |
|---|---|---|
| S | Under 50,000, with 2 or fewer external integrations | All plans |
| M | 50,000–200,000 | Standard, Critical |
| L | 200,000–500,000 | Standard, Critical |
| XL | Over 500,000, or multiple systems | Case by case |
Hours included in your monthly fee cover all in-scope work: fixes, minor changes, and required SDK updates. Unused hours roll over to the next month, up to one month's worth of included hours, with no refunds. Overage is US$138 per hour, quoted before work begins and billed at month-end.
Prices exclude tax and are monthly rates on an annual contract. Final size and plan are confirmed by the takeover assessment. If we miss a response time, the monthly fee is credited pro rata.
Scope of service
What we do and don't do, made clear before you sign.
Included in the contract
- Code analysis, bug fixes, hotfixes
- Code-level troubleshooting of production issues
- Regression testing, code review, release support
- Source documentation and knowledge base upkeep
- Dependency and build issues(existing versions only)
- Minor change requests(included hours first; beyond that, quoted separately)
- Required SDK updates for App Store / Google Play policies(included hours first; beyond that, quoted separately)
Not included
- Day-to-day server, database, and network operations
- New features or large development projects
- Rewrites or migration to new technology
- Systems without legal rights to the source code
Can we take over your legacy system?
Check the conditions you already meet. The takeover assessment will help fill in anything missing.
Legacy maintenance FAQ
Why not just rewrite the system?
A rewrite means rediscovering every business rule buried in the old system, and its cost and risk are usually underestimated. If the system still has 3 to 5 years of service left, stable maintenance is the better deal. If you do decide to rewrite later, the knowledge base and test baselines we build can go straight to the new team.
How do you use AI?
We use AI to read code, build the knowledge base, and draft test cases and fixes. Every change is reviewed by an engineer and passes regression tests before delivery.
Is our source code safe?
Your source code is kept in a dedicated, isolated environment, and both parties sign an NDA. We only use enterprise AI services that do not retain your data or train on it. Your contract can also require on-premises models only.
Will we be locked in when the contract ends?
No. The source code, documentation, build scripts, and tests all belong to you. When the contract ends, we hand everything back along with handover notes.
How do you measure codebase size?
We count lines of custom code plus database stored procedures, excluding tool-generated code (such as VB6 forms and WinForms designer files) and third-party libraries. For an initial consultation, just run scc or cloc in your source directory and send us the output. The official size is confirmed during the takeover assessment, which also considers the number of external integrations and third-party components.
Can you maintain a mobile app without updating it?
We can maintain existing features, but an app can never stand completely still. Google Play raises its target API level requirement every year, and the App Store requires submissions built with recent Xcode and SDK versions. Fall behind, and you can no longer ship updates or stay listed. These required updates draw on the hours included in your monthly fee first; anything beyond that is quoted separately. We notify you early each year once the new policies are announced. Before takeover, please also confirm that the signing certificates, Android keystore, and developer accounts are registered to your company. If the keystore is lost, the existing app can never be updated again.
If nothing breaks in a month, isn't the fee wasted?
No. Included hours can be used for any work within the contract scope, including minor changes (such as report fields, calculation rules, or screen adjustments) and required SDK updates. Unused hours roll over to the next month, up to one month's worth of included hours. Hours not used by then expire and are not refunded. Each monthly report shows hours used, rolled over, and about to expire.
What if the assessment shows you can't take it on?
The assessment report states the reasons, such as source code that doesn't match production or licenses for key components that can't be obtained. You can take the report to other vendors, with no obligation to sign a maintenance contract.
Book a takeover assessment
Tell us briefly what the system does and what it's built with. We'll reply with an initial assessment within 2 business days.
- Reply within 2 business daysAn initial read on whether we can take it over, and roughly how long it will take
- NDA before we see any codeNo source code needed for the initial consultation
- Emaillegacy@jetsion.com
- Phone+886 982-271-987