Modernizing a Delphi system often feels like walking into a maze with no map. There’s no documentation. The only person who understood the logic retired years ago. And you’re staring at code full of outdated components and fragile integrations.
At Softacom, we’ve seen it all. In 20+ years, we’ve worked with 125+ million lines of legacy Delphi code, from ANSI strings and BDE to Unicode, FireDAC, and 64-bit architecture. We’ve dealt with broken DevExpress styles, incompatible serialization and broken master-detail relationships in kbmMemTable, graphs breaking after migration with TeeChart, and systems that still run on FTP and SOAP.
In this guide, we have collected the most common issues that come up during Delphi modernization and how we recommend solving them.
Outdated Components
Alex Azarou
Director of Information Technology“Some of these third-party components haven’t been updated in over a decade. The deeper they’re embedded, the more risk they carry.”
Delphi has thousands of third-party components, but not all are maintained, which might also cause a problem with licensing.
The deeper third-party components are embedded into the project, the higher the chance you’ll face compilation errors or unexpected behavior during migration. In our experience, the most common issues include:
- Changes in internal component logic or behavior, including fixes or removed legacy features.
- Compilation breaks due to new packages, modules, data types, constants, procedures, or conditional compilation symbols introduced in newer versions.
These issues often surface in subtle ways, and the more your app relies on these components, the more time and care will be required to resolve them during migration.
Typical problems include:
- Unicode conflicts. Legacy components often don’t support Unicode, leading to corrupted text or broken logic.
- Removed or deleted components. For example, instead of TDBExpress, there is TFDConnection. In this situation, it is better to switch to new components, from DBExpress to FireDAC or UniDAC. You can also use conditional directives ({$IFDEF}) to support both old and new Delphi versions in the same codebase.
- No 64-bit support in older versions of Delphi. You need to update the calling of APIs.
- Third-party components. Many old components are not compatible with newer versions of Delphi.
Softacom’s Approach
One of the solutions is to update all the components to a newer Delphi version and adapt the usage of components in the newer version.
Here are some alternatives you can use:
| Component | Alternative |
| TeeChart | TAChart, FMXGraphics, HighResChart |
| kbmMemTable | FireDAC.TFDMemTable, DevExpress.TdxMemData |
| DevExpress | TMS, LMD |
Lost Knowledge
The original developers are gone. The documentation is outdated or missing. And now, you are left trying to modernize code you barely understand.
Business logic is often buried deep in forms, event handlers, and database queries, with no clear structure or explanation. Worse, naming is often cryptic with unclear variable, constant, procedure, or data type names that make the code hard to follow. In some cases, even SQL queries or arbitrary text strings are “encrypted” in ways that only the original developer understood. Some features exist simply because “it always worked that way.”
Softacom’s Approach
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