If you have been working with ContaPlus —now rebranded as Sage 50— and are evaluating the switch to Contasol, you are not alone. Since Sage redesigned its licensing policy and raised maintenance costs, hundreds of accountancy firms and professional offices across Spain have made the transition to Contasol, the professional accounting solution from the TeamSystem/DELSOL group. This article explains what the migration involves, what data you can carry over, how to plan the change without disrupting your clients' service, and what advantages you gain in view of the upcoming Verifactu obligation.
Why accountancy firms are leaving ContaPlus/Sage 50
ContaPlus was born in the 1990s as one of the first accounting programs for Spanish SMEs. For decades it was the de facto standard in many firms. However, its integration into the Sage portfolio brought a subscription model that many users consider expensive relative to the actual features offered, especially in firms managing a medium-to-high number of companies.
The most frequent reasons we hear at Summum Sistemas when analysing each case are three:
- Rising subscription costs without noticeable functional improvements for the firm's day-to-day work.
- Outdated file architecture that complicates network collaboration and remote access.
- Uncertainty around Verifactu: firms want to be sure that whichever software they choose is already adapted or will be in time before January 2027 for legal entities and July 2027 for sole traders.
Contasol addresses all three points: its price is substantially lower (with a free 30-day trial, no commitment required), its architecture supports network working and a cloud mode with Contasol Cloud, and the TeamSystem/DELSOL group already has an SII module integrated —incompatible with Verifactu for companies already on SII, but ready for those that are not— and is working on the Verifactu adaptation of the suite.
What is Contasol and who develops it
Contasol is the professional accounting module of Software del Sol (DELSOL), a company based in Mengíbar (Jaén) acquired by the Italian group TeamSystem in February 2021. TeamSystem is the largest SME management software group in Italy, with more than 3.1 million clients in Europe and turnover exceeding 1,150 million euros in 2025.
Contasol covers the full accounting cycle: manual and automatic journal entries, VAT returns (303, 390, 349), personal income tax (130, 131), corporate income tax (200), annual accounts in accordance with the Spanish General Chart of Accounts, and the Immediate Supply of Information (SII) for companies with annual turnover above 6 million euros. It is available in four versions:
| Version | Users | Indicative price | Mode |
|---|---|---|---|
| Free trial (30 days) | 1 | 0 EUR | Desktop (Windows) |
| Standard | Multiple | ~155 EUR/year (indicative) | Desktop (Windows) |
| Elite | Multiple + advanced features | ~415 EUR/year (indicative) | Desktop (Windows) |
| Cloud | Per user | From ~21 EUR/user/month (indicative) | Web browser |
Note: prices are indicative from the manufacturer and may vary. Always check the current rates at sdelsol.com.
At Summum Sistemas we are an Official TeamSystem Partner and we implement and migrate Contasol in accountancy firms and professional offices throughout Castilla y León and the Canary Islands. For full details of the service, visit our Contasol implementation and support page.
Key differences between ContaPlus/Sage 50 and Contasol
Before migrating it is worth understanding the similarities and differences between the two environments. Both work on the Spanish General Chart of Accounts and produce the same tax returns, but there are workflow differences that affect how long the team takes to adapt.
- Chart of accounts: Contasol uses the standard chart of accounts with the same numbering as ContaPlus. Adapting each company's customised chart of accounts is the most delicate step in the migration.
- Data files: ContaPlus/Sage 50 stores data in proprietary .con / .emp files. Contasol uses its own database. The intermediate export is usually done in ASCII or Excel format.
- Interface: Contasol has a short learning curve for ContaPlus users because the logic for journal entries, the day book and the ledger are equivalent. In the first few days users notice naming differences that disappear after a week of use.
- Integration with invoicing: Contasol integrates natively with Factusol (invoicing and stock), also from TeamSystem/DELSOL. If your firm also manages clients' invoicing, the DELSOL 360 suite combines both modules in the cloud.
- SII: Contasol includes the SII module. Sage 50 does too, but the configuration differs. When migrating, digital certificates and AEAT endpoints must be reconfigured.
Step by step: how to migrate from ContaPlus to Contasol
1. Inventory and preliminary closing
Before touching anything, make an inventory of the companies you manage in ContaPlus: number of companies, open financial years, periods with outstanding entries to balance, whether you use SII and for which financial years. Also define the cut-off point: the most common approach is to migrate at the start of the financial year (1 January) with the opening balances, without carrying over the full historical journal. If you need the history for reference, you can keep the old installation in read-only mode.
2. Exporting data from ContaPlus/Sage 50
Sage 50 allows you to export the chart of accounts and current-year journal entries in Excel or CSV format from the utilities menu. The minimum fields you need are: account code, description, debit, credit, date, concept and document number. Also export accumulated balances from previous financial years if you need them for future audits or tax inspections.
3. Preparing Contasol: companies and chart of accounts
In Contasol you create each company from scratch with its fiscal data (tax ID, address, VAT regime, financial year). You then import the chart of accounts from the exported Excel file. Contasol has an import wizard that maps columns; if your chart of accounts follows the standard chart, the mapping is nearly automatic. Customised sub-accounts (suppliers, clients, creditors) are also imported in bulk.
4. Importing opening balances
With the chart of accounts ready, you enter the opening balances (journal entry 0 of the financial year) from the closing balances of the previous year. This is the most critical step: always check that assets balance against liabilities before validating the opening entry. Contasol has a verification screen that alerts you if the opening entry is unbalanced.
5. Migrating current-year journal entries (if applicable)
If the migration takes place mid-year, the already-posted journal entries must also be transferred. In this case the import is more delicate: journal entry numbers must be preserved and the debit and credit totals must match period by period against ContaPlus statements. We recommend doing this company by company and validating the trial balance after each import.
6. Reconfiguring tax returns and SII
Each company needs its VAT rates, input and output VAT accounts, and —if applicable— the SII connection parameters (representative tax ID, digital certificate) configured. This phase takes between 15 and 45 minutes per company depending on complexity. At Summum Sistemas we handle this in our migration projects so that the firm's team does not lose time on technical configuration.
7. Team training and run-in period
The learning curve for an accountant who knows ContaPlus is short. In our experience, after a two-hour session the team is already working fluently in the new environment. We recommend a four-week run-in period during which support is available to resolve operational questions: keyboard shortcuts, generating tax returns, exporting reports.
Contasol and Verifactu: what you need to know before 2027
One of the reasons this is a particularly relevant moment to migrate is the upcoming Verifactu obligation, regulated by Royal Decree 1007/2023 as amended by RDL 15/2025. The current deadlines are:
- Legal entities: mandatory compliance from 1 January 2027.
- Sole traders: mandatory compliance from 1 July 2027.
It is important to clarify a point that often causes confusion: there is no «homologation» of software by the AEAT. The legal mechanism is the manufacturer's declaration of conformity under RD 1007/2023. The manufacturer declares that its software meets the technical requirements; there is no official list of «certified» software nor a prior approval process from the Tax Agency.
It is also worth knowing that SII and Verifactu are mutually exclusive: companies already required to use SII (annual turnover above 6 million euros) will not have to adopt Verifactu. For all others, the invoicing software —Factusol, Billin and the Aplifisa suite of FactuGes— already has the adaptation under way. Contasol, as accounting software rather than invoicing software, is not directly affected by Verifactu, but the integration with whichever invoicing module you use is.
If your firm also handles client invoicing with Factusol, moving to the DELSOL 360 suite (Factusol + Contasol + Nominasol in the cloud) gives you a clear, single roadmap to comply with all tax regulations before the deadlines. Full details are on our Contasol service page.
How long does the migration take
It depends on the number of companies and the state of the accounts. As a rough guide:
- Firm with 10–30 companies: between 3 and 5 days of technical work spread over two weeks (to avoid cutting daily operations).
- Firm with 30–100 companies: between 2 and 4 weeks, with batch imports and validation by groups.
- Firms with more than 100 companies: bespoke projects; typically done in waves over a full quarter.
The factor that extends the migration most is not the technical import but the balance verification: reconciling company by company, detecting unbalanced entries or incorrectly mapped sub-accounts. That is why it is essential to carry out the migration with a proper methodology rather than in an improvised way.
Advantages of migrating now rather than waiting
The sooner the migration is done, the more time the firm's team has to work with the new software before the busiest tax periods (April for corporation tax, July for income tax). Migrating in January is ideal; doing it in March or April, with tax returns looming, multiplies the risk of errors. Migrating now also gives time to resolve any issues without pressure and to take advantage of the integration with the DELSOL 360 suite if you later want to unify invoicing, accounting and payroll in a single cloud environment.
At Summum Sistemas we have been accompanying companies and professional offices in management software implementations and migrations since 2007, with more than 2,000 projects completed and five offices in Valladolid, Burgos, Palencia, Aranda de Duero and Las Palmas de Gran Canaria. The team that assists you knows Contasol in depth and has managed migrations from ContaPlus, a3ASESOR and Sage Despachos.
Frequently asked questions
Can I migrate only the opening balances or also the full journal history?
Both options are possible. Migrating opening balances is the fastest and the one we recommend in most cases: the firm starts the new financial year in Contasol with clean balances and keeps read-only access to ContaPlus for historical queries. Migrating the full journal makes sense when the firm needs to work with current-year entries in Contasol without relying on the previous program.
Is data lost when exporting from ContaPlus to Contasol?
If the export and import are done with the correct methodology, no relevant information is lost. The chart of accounts, balances, journal entries and company data are transferred in full. What is not migrated are ContaPlus screen configurations or custom reports, which must be recreated in Contasol. Historical tax data (submitted returns) remain in ContaPlus; there is no need to migrate them because you will have kept them as PDFs or in the AEAT system.
Does Contasol work on a network for several simultaneous users?
Yes. The Standard and Elite versions support local network working with multiple simultaneous users. The Cloud version (Contasol Cloud) is accessible from any browser and removes the need for a local server: several staff members can work at the same time from different locations. This option is especially useful for firms with remote working or multiple offices.
What happens with SII if my clients are already registered?
When migrating to Contasol, you must reconfigure the SII parameters for each already-registered company: digital certificate, representative tax ID (where the firm acts as representative) and the VAT accounting accounts. Invoice records already submitted to the AEAT's SII do not need to be resubmitted; only new entries from the migration date onwards are affected. We also recommend reading our article on Contasol and SII for more detail on the technical configuration.