Construction company seeks expandable complete commercial solution

We are a construction company based in southern Germany specializing in facade, window, and door construction, and we are looking for a comprehensive business solution tailored to our needs. If necessary, the solution should be expandable to a company-wide solution.

The software should meet the following requirements:

• Customer management
• Financial accounting for the construction sector (windows, doors, and facade construction) with the typical special features (partial payments, invoices)
• Invoicing
• Quotations
• Orders
• Delivery notes
• Invoices (partial invoices, final invoices)
• Open item management
• Dunning
• Security retention
• Project evaluation of construction sites
• Support for mobile devices (Android)
• On-premises or web-based
• Scalable

The software we are looking for must include financial accounting; no data should be transferred to an external financial accounting system (no interface).

Four to six software workstations are planned. We work with MS Windows systems.