Dynamics SL end of support (2028): moving US project-based firms to ERPNext Projects and Accounting
Short answer
Microsoft’s lifecycle page shows Dynamics SL 2018 Extended Support ending July 11, 2028 (mainstream support already ended in January 2024), and Microsoft says that on January 15, 2030 Service Plan coverage for SL ends and you can no longer add perpetual users (checked Nov 14, 2026). Microsoft’s recommended path is Dynamics 365 Business Central online, and its migration tool brings over SL ledgers, open receivables and payables, items and Project Controller master data (projects, tasks, resources), not your project transaction history. For a US project-based firm or contractor of roughly 20 to 150 users, the decision comes down to one question: can the replacement reproduce your project costing and billing? Business Central is the low-risk default if you want to stay with Microsoft. ERPNext is worth a serious look if you want no per-user licence fee, your billing is mostly time and materials, fixed fee or milestones, and you are not relying on SL for government-contract indirect rate work. ERPNext has no licence fee (GPL-3.0); Frappe Cloud hosting starts at $5 a month for a site and $40 for a server. Business Central lists Essentials at $80 / £61.50 and Premium at $110 / £84.60 per user per month, paid yearly (UK prices exclude VAT).
Contents
- Who this guide is for
- What Microsoft actually says about SL
- The real question: can the new system carry your project accounting?
- The Microsoft path: Business Central, and what the migration tool moves
- Where ERPNext fits a project-based firm
- Mapping SL project costing and billing to ERPNext
- A four-week fit test before you choose
- Cost: what can be compared honestly
- If you choose ERPNext: an SL migration plan
- Business Central, ERPNext or something else: a decision table
- Best for, and wrong choice when
- Frequently asked questions
Who this guide is for
This guide is for controllers, CFOs, project accounting leads and IT managers at US project-based firms that still run Microsoft Dynamics SL (the product many people still call Solomon): engineering and professional services firms, specialty contractors, and other businesses where the project, not the product, is the unit of profit. We have written it for sites of roughly 20 to 150 SL users on SQL Server, usually with a long-standing partner.
We build and support ERPNext. That does not make it the right answer for every SL site, and we say clearly below where Business Central or a specialist project ERP is the better move. What we want to give you is a practical way to check whether ERPNext can carry your project costing and billing, because that is where SL replacements succeed or fail.
This guide is part of our series on legacy ERP deadlines; the legacy ERP end-of-support hub lists every vendor date we have confirmed. Many SL customers also run Dynamics GP elsewhere in the group, so our Dynamics GP to ERPNext guide may also apply. If you are an architecture or engineering firm comparing project ERPs, the Deltek Vision guide covers the same fit test from another angle.
Sources, all checked on Nov 14, 2026: Microsoft Lifecycle: Dynamics SL 2018, the Microsoft Lifecycle FAQ for Dynamics, the Microsoft Dynamics SL Directory and Microsoft’s GP and SL migration options post (June 5, 2025) for dates; Microsoft’s Dynamics SL to Business Central online migration overview and Microsoft’s list of Dynamics SL data migrated to Business Central for the Business Central path; Business Central pricing page (US) and Business Central pricing page (UK) for prices; the Frappe Cloud pricing page, ERPNext repository on GitHub and the ERPNext documentation linked in each section for ERPNext.
What we do not do here
We do not estimate implementation fees for either option, and we do not quote any partner’s rates. Business Central licence prices below come from Microsoft’s own pricing pages. Everything else depends on your modules, data volume and billing rules.
What Microsoft actually says about SL
| Milestone | Date | Source |
|---|---|---|
| Dynamics SL 2018 mainstream support ended | January 9, 2024 (shown as 1/10/2024 6:59:59 AM PT on the lifecycle page; moved from July 11, 2023) | Microsoft Lifecycle: Dynamics SL 2018 |
| Dynamics SL 2018 Extended Support ends (end of support) | July 11, 2028 (shown as 7/12/2028 6:59:59 AM PT) | Microsoft Lifecycle: Dynamics SL 2018 and Microsoft Lifecycle FAQ for Dynamics |
| Service Plan coverage (for example Enhancement Plan) ends for SL | January 15, 2030 | Microsoft Dynamics SL Directory and Microsoft’s GP and SL migration options post (June 5, 2025) |
| Last day to license more perpetual users on existing SL systems | January 15, 2030 | Microsoft’s GP and SL migration options post (June 5, 2025) |
| SL through SPLA subscriptions | Expected to end January 15, 2030 (Microsoft’s wording is “expected”) | Microsoft Dynamics SL Directory |
Two things are worth reading carefully. First, Microsoft’s 2025 post says mainstream support ended July 11, 2023, while the lifecycle page and FAQ say the mainstream date was moved to January 9, 2024. The lifecycle page is the authoritative record, so we use January 2024. Either way, SL is already in Extended Support today.
Second, the January 2030 date is not an extension of support. Microsoft is clear that Extended Support, which covers security updates, ends on July 11, 2028. The 2030 date is about licensing: when the Service Plan stops and when you can no longer add users.
Why “Extended Support” already matters for a US firm
Microsoft’s Dynamics lifecycle FAQ says tax and regulatory updates for supported Dynamics products are released, generally each fiscal year or as needed, for software in the Mainstream Support phase, and that you need an active Enhancement Plan or Software Assurance to receive non-security updates and tax and regulatory releases. SL 2018 left mainstream support in January 2024. In practice that means you should not plan on new functionality, and you should check with your partner exactly what tax, 1099 and payroll updates your SL estate will still receive between now and July 2028.
Microsoft’s own recommendation, in the FAQ, is that SL customers “should consider migrating to Dynamics 365 Business Central online”.
The real question: can the new system carry your project accounting?
An SL replacement is rarely about the general ledger. Every serious ERP can post journals, run payables and produce a trial balance. SL earned its place in US project firms because of the project modules around the ledger: Project Controller for the project and task structure, budgets by project and task, time and expense entry, project billing and revenue recognition, and, at some firms, allocation of overhead and other indirect costs onto projects.
So the evaluation has to start there. Before you look at a single demo, write down the answers to these questions, using your actual SL configuration:
Your SL project profile
- How many active projects and tasks do you carry, and how deep is the work breakdown you actually report on?
- Which billing types do you use: time and materials, fixed fee, percent complete, milestone, cost plus, retainage, unit billing?
- How do you recognise revenue, and does your auditor care about the method?
- Do you allocate fringe, overhead or G&A onto projects, and do contracts depend on those rates?
- Who enters time and expenses, and how are they approved?
- Which project reports do your project managers and owners read every month?
- Which integrations feed SL: payroll, CRM, document management, scheduling, a construction estimating tool?
Firms whose answers are mostly “time and materials, fixed fee and milestones, standard reports, approvals by project manager” are good ERPNext candidates. Firms with heavy cost-plus government work, provisional indirect rates and incurred-cost reporting are usually not, and we say so again in the decision section.
The Microsoft path: Business Central, and what the migration tool moves
Microsoft provides a cloud migration tool from SL 2015 or later to Business Central online. Its documentation describes how it works: data is replicated from your on-premises SQL Server database into the Business Central online database through Azure Data Factory, table by table, with success and failure tracked per table. Microsoft recommends a test run in a sandbox first and warns against setting up cloud migration for a production environment that is already in use. It also provides SL Analysis and Repair tools on GitHub to assess your database before you start.
What the tool migrates, according to Microsoft:
| SL data | In Business Central after migration |
|---|---|
| Fiscal periods | Accounting periods (historical years arrive open and must be closed) |
| Chart of accounts and subaccount segments | Accounts, with subaccount segments set up as dimensions (two global, the rest shortcut dimensions) |
| GL history | Summary transactions per fiscal period, from the oldest historical year you choose |
| Customers and open receivables | Customers (all or active only) and open documents at the remaining amount |
| Vendors and open payables | Vendors (all or active only) and open documents at the remaining amount |
| Inventory items | Items with cost method, locations, quantity on hand, and serial or lot information |
| Project Controller | Master data only: projects (Active or Plan), tasks (Active) and resources (Active or On Hold) |
| Historical detail (optional) | A read-only “Dynamics SL Detail Snapshot” in extension tables for GL, AP, AR, sales order, purchase receipts and inventory transactions |
Read the last two rows twice. Project master data comes across. The snapshot list Microsoft publishes covers GL, payables, receivables, sales orders, purchase receipts and inventory, but it does not list Project Controller transactions, project budgets, unbilled work in progress or billing history. Whichever destination you choose, plan to rebuild open project budgets and carry unbilled time and costs across deliberately. That is a point in ERPNext’s favour only in the narrow sense that the Microsoft path is not “lift and shift” for the project side either.
Business Central prices (official, checked Nov 14, 2026)
| Plan | US (per user / month, paid yearly) | UK (per user / month, paid yearly, excl. VAT) |
|---|---|---|
| Business Central Essentials | $80.00 | £61.50 |
| Business Central Premium (adds service management and manufacturing) | $110.00 | £84.60 |
| Team Members (read, approve workflows, update select information) | $8.00 | £6.20 |
Licence list price for a year, from those figures (users × monthly price × 12; no discounts, partner fees or add-ons):
| Full users | Essentials (US / UK excl. VAT) | Premium (US / UK excl. VAT) |
|---|---|---|
| 20 full users | $19,200 / £14,760 | $26,400 / £20,304 |
| 50 full users | $48,000 / £36,900 | $66,000 / £50,760 |
| 100 full users | $96,000 / £73,800 | $132,000 / £101,520 |
Both GBP columns are Microsoft’s own UK prices, not conversions. Most US project firms would buy Essentials; Premium matters if you also need service management or manufacturing. Add any project-accounting ISV app your partner recommends, which is priced separately by its publisher.
Where ERPNext fits a project-based firm
ERPNext is open source under GPL-3.0, so there is no per-user licence. Its Projects module sits on the same ledger as accounting, buying, selling, stock and HR. From the ERPNext documentation:
- The ERPNext Projects module overview describes projects as the central point for tasks, timesheets, expenses and billing, with invoices based on time logs, milestones or fixed project values.
- A project tracks costing and billing: the ERPNext Project documentation lists costing from timesheets, expense claims, purchases and consumed material, and a gross margin calculated against billed and billable amounts.
- The ERPNext Timesheet documentation carries billing hours, billing rate and costing rate per row; the costing rate comes from ERPNext Activity Cost documentation per employee or from the activity type.
- The ERPNext Budget documentation lets you budget against a cost center, a project or an accounting dimension, and choose to warn or stop when a material request, purchase order or posted expense exceeds the budget.
- The ERPNext accounting dimensions documentation and ERPNext Cost Center documentation give you the extra reporting segments that SL users usually hold in subaccounts.
- A ERPNext Project Template documentation lets you start each new contract type with a standard task list.
- ERPNext Payment Terms documentation and ERPNext Sales Order documentation support milestone schedules on the commercial side.
That covers the core of SL project accounting for most commercial firms: structure, budgets, time, expenses, costing and invoicing. What it does not give you out of the box is SL’s depth in revenue recognition methods and indirect cost allocation. Those either become configuration and journal discipline, a scoped custom build, or a reason to choose something else.
Mapping SL project costing and billing to ERPNext
This is the table we use in discovery. It is a starting point, not a promise: your SL configuration decides the details.
| Dynamics SL | ERPNext | What to check |
|---|---|---|
| Project Controller: project | Project (linked to customer, cost center and optionally a sales order) | Keep your SL project IDs as ERPNext project names; staff know them |
| Project tasks (work breakdown) | Tasks and sub-tasks under the project | Load only the levels you budget and report on |
| Account categories (labour, travel, subcontract, materials) | Expense accounts plus accounting dimensions or item groups | Decide whether categories live in the chart of accounts or in a dimension |
| Subaccount segments | Cost centers and accounting dimensions | Map one SL segment to one dimension; do not mix |
| Project budgets | Budget against project and account, warn or stop | Budget at the level PMs manage; revisions become amended budgets |
| Labour rates and employee cost | Activity Type and Activity Cost (billing and costing rate per employee) | Fully burdened rates need an agreed method |
| Time entry | Timesheet against project and task, billable flag | Mobile entry and approval route |
| Expense entry | Expense Claim linked to project | Card feeds and receipts |
| Subcontractor and vendor costs | Purchase Order and Purchase Invoice coded to project | Retainage on payables needs a design |
| Project billing: time and materials | Sales Invoice from timesheets | Rate overrides and markup rules per contract |
| Project billing: fixed fee and milestones | Sales Order with payment terms, invoice per milestone | Percent-complete billing needs a report or a custom step |
| Revenue recognition | Journal entries driven by project reports, or a custom routine | The biggest design item for most SL sites |
| Allocator (overhead, fringe, G&A onto projects) | Periodic allocation journals or a custom allocation routine | If contracts depend on these rates, see the decision section |
| Customers, vendors, AR and AP | Customer, Supplier, open invoices via the Opening Invoice Creation Tool | Load open items at remaining amounts |
| General ledger history | Opening balances plus summarised monthly history if needed | Keep SL read-only for detail |
The three hardest items
- Unbilled work in progress. Every hour and cost worked but not billed at cutover must arrive in ERPNext as billable timesheets or costs against the right project and task, or be billed in SL first. Reconcile unbilled WIP to the penny in each dress rehearsal.
- Revenue recognition. If you recognise revenue on percent complete or cost-to-cost, agree the method with your auditor and build the monthly routine before go-live, not after.
- Indirect rates. If SL’s allocation runs drive what you bill, prove the ERPNext equivalent reproduces last quarter’s numbers before you sign anything.
A four-week fit test before you choose
We recommend running this on your own data before you request either a Business Central or an ERPNext implementation quote. It costs a few weeks of finance and project manager time and saves months of argument later.
Week 1: structure
Pick six live projects that represent your mix: one large multi-phase project, one fixed-fee job, two time-and-materials projects, one with heavy subcontract costs and one internal or overhead project. Rebuild their structure, budgets and rates in ERPNext.
Weeks 2 and 3: one month of transactions
Load one closed month of real time, expenses and vendor costs for those projects. Run the costing, then produce the invoices you actually sent for that month.
Week 4: reconcile and decide
Pass criteria
- Project cost for the month matches SL by project and task, or every difference is explained.
- Invoices match SL line for line for time-and-materials work, and milestone invoices follow the contract.
- Budget versus actual by project and task is readable by a project manager without help.
- The revenue recognition method you use can be produced for the month, even if by a documented journal routine.
- Any indirect rate allocation reproduces SL’s result for the month.
- Finance can close the month in ERPNext without exporting to spreadsheets.
How to read the result
If revenue recognition or allocations need significant custom code, count that as a permanent maintenance cost. A Business Central project that keeps those routines inside a supported ISV app may be worth more than an ERPNext licence saving.
Cost: what can be compared honestly
| Item | Business Central | ERPNext |
|---|---|---|
| Licence | Essentials $80 / £61.50, Premium $110 / £84.60, Team Members $8 / £6.20 per user / month, paid yearly (UK excl. VAT) | No licence fee (GPL-3.0) |
| Hosting | Included in Business Central online | Frappe Cloud sites from $5 / month, servers from $40 / month, or self-host |
| Migration tooling | Microsoft cloud migration tool for ledgers, AR/AP, items and project masters | Data Import templates and opening-balance tools; project history rebuilt |
| Project accounting depth | Standard projects plus optional ISV apps (priced by the publisher) | Projects module; revenue recognition and allocations configured or built |
| Implementation | Partner quote | Partner quote |
Frappe Cloud publishes USD prices: site plans from $5 a month (about £3.78) and servers from $40 a month (about £30.22), checked on Nov 14, 2026. The GBP figures are indicative conversions, not Frappe prices.
Indicative GBP conversions use the Bank of England daily spot rate (series XUDLUSS) of US$1.3238 per £1 for 12 Nov 2026, the latest published figure when we checked on Nov 14, 2026. They are not official UK prices: the vendor does not publish a GBP list price for these items, and your invoice currency, rate and VAT treatment may differ.
Because implementation is the larger cost on both sides, the honest comparison is two written quotes for the same scope and the same fit-test results, over five years. Licence savings on ERPNext become meaningful as user counts rise, but only if the fit test showed little custom work on billing and revenue recognition.
If you choose ERPNext: an SL migration plan
| Phase | Work | Done when |
|---|---|---|
| Fit test (4 weeks) | Six projects and one month, as above | Written go or no-go, with a Business Central quote alongside |
| Discovery (4–6 weeks) | Billing types per contract, revenue recognition, allocations, reports, integrations, history policy | Signed scope; every billing pattern has a configuration or a scoped build |
| Build (3–5 months) | Chart of accounts and dimensions, projects and templates, rates, invoice formats, budget controls, reports, integrations | User acceptance signed by finance and two project managers |
| Dress rehearsals (2 cycles) | Trial loads of masters, open projects, budgets, unbilled WIP, open AR/AP and balances | Unbilled WIP, AR, AP and trial balance agree with SL |
| Cutover (month end, ideally year end) | Close SL, load openings, go live, first billing run | First month closed and invoices sent from ERPNext |
These are planning ranges from our own projects for firms of this size, not a quote. Use ERPNext Data Import documentation for masters and ERPNext opening balance documentation guidance for opening balances and open invoices. Keep SL available read-only (or extract it to a reporting database) for project history and audit; do not try to migrate years of transaction detail.
Timing matters. If you start in 2026 you can finish comfortably before July 2028 and avoid running SL without security updates. Starting in 2028 leaves no room for two dress rehearsals and a clean year-end cutover.
Business Central, ERPNext or something else: a decision table
| If this is true for you | Lean towards | Why |
|---|---|---|
| You want to stay with Microsoft and your partner, and use standard project billing | Business Central | Microsoft’s migration tool, familiar partner, published prices |
| You rely on Microsoft 365 and Power Platform integration across the business | Business Central | Tighter fit with the Microsoft stack |
| Your billing is mostly time and materials, fixed fee and milestones, and you want no per-user licence | ERPNext (price both) | Projects, timesheets, budgets and invoicing on one ledger |
| You also run stock, fabrication or field work alongside projects | ERPNext (price both) | Projects, stock and manufacturing in the same open-source system |
| You want to self-host or control the code and database | ERPNext | Open source; self-host or choose a Frappe Cloud region |
| You are a US government contractor relying on SL for indirect rate allocations and incurred-cost reporting | A specialist government-contract project ERP, or Business Central with a dedicated ISV app | ERPNext would need significant custom work to match that compliance depth |
| You are under 12 months from July 2028 with no plan | Business Central | The Microsoft tool and an experienced SL partner are the fastest route |
Best for, and wrong choice when
ERPNext is best for
US commercial project firms and contractors with roughly 20 to 150 users, whose billing is mostly time and materials, fixed fee or milestones, who want to stop paying per user, and who can give finance and project managers time for a fit test and two dress rehearsals.
Business Central is best for
SL customers who want the shortest supported path, value the Microsoft ecosystem and their existing partner, and are comfortable with a per-user subscription in exchange for Microsoft’s migration tooling.
ERPNext is the wrong choice when
Your revenue depends on government-contract indirect rates, provisional billing rates and incurred-cost submissions that SL handles today; your revenue recognition method is complex and nobody wants to redesign it; or you need to be off SL in a few months.
Frequently asked questions
When does Dynamics SL support end?
Microsoft’s lifecycle page shows Extended Support for Dynamics SL 2018 ending July 11, 2028. Mainstream support ended January 9, 2024 (checked Nov 14, 2026).
What happens on January 15, 2030?
Microsoft says Service Plan coverage for Dynamics SL ends, you can no longer add perpetual users to existing SL systems, and use of SL through SPLA subscriptions is expected to end. It is not an extension of security support.
Will SL keep working after July 2028?
An on-premises system does not switch off, but Microsoft will no longer provide security updates or support for it. Running finance and payroll on unsupported software is a risk most auditors and insurers will ask about.
Does Microsoft’s migration tool move SL project data to Business Central?
It moves Project Controller master data: projects in Active or Plan status, active tasks and resources. Microsoft’s published list of migrated history covers GL, AP, AR, sales orders, purchase receipts and inventory, not project transactions, budgets or billing history.
Can ERPNext handle project costing and billing for a contractor?
ERPNext projects track costs from timesheets, expense claims, purchases and materials, and invoice on time logs, milestones or fixed values. Budgets can warn or stop overspend by project. Revenue recognition methods and indirect cost allocations need design and should be proven in a fit test.
How much does Business Central cost?
Microsoft lists Essentials at $80 and Premium at $110 per user per month, paid yearly, in the US; the UK prices are £61.50 and £84.60 excluding VAT. Team Members are $8 / £6.20 (checked Nov 14, 2026).
How much does ERPNext cost?
ERPNext has no licence fee under GPL-3.0. Frappe Cloud lists sites from $5 a month and servers from $40 a month (USD, checked Nov 14, 2026). Implementation and support are extra.