CUDA, Driver and Framework Version Compatibility

CUDA version errors often come from treating several layers as if they were one version number. The NVIDIA driver runs on the host and manages the GPU. A CUDA toolkit contains development tools and libraries; a runtime distribution may include only what an application needs. Deep-learning frameworks are built or packaged against particular CUDA and cuDNN versions, and containers may carry some user-space libraries while relying on the host driver. NVIDIA documents driver compatibility modes, including backward compatibility in which a sufficiently new driver can run applications built with older CUDA toolkits. Some forward-compatibility paths use compatibility packages under specific platform and GPU conditions. These rules do not mean any arbitrary driver, toolkit and framework can be mixed. Framework releases publish their own supported installation combinations, and platform support can differ. A failure should be diagnosed layer by layer. First confirm the host driver recognizes the GPU. Then inspect the framework build's CUDA support and whether the runtime can initialize. In a container, confirm GPU runtime integration and device exposure. Finally run an operation that launches a kernel; successful imports or device enumeration alone may not prove all required libraries are compatible. Error messages can come from missing shared libraries, driver API mismatch, unsupported GPU architecture or package conflicts. For reproducibility, record operating system, GPU model, host driver, container image, framework version and framework's CUDA build. Prefer official installation selectors or compatibility matrices instead of independently installing multiple toolkits until one works. A development environment may need a compiler toolkit, while an inference image can often use runtime libraries. Update one layer at a time and retest. Version labels are useful clues, but compatibility is defined by supported interfaces and release requirements, not identical numbers across all components.