The ViennaRNA Package 2.0 is an updated version of the widely used software for RNA secondary structure prediction and analysis. This package has been extensively revised to incorporate major changes in the standard energy model, the Turner 2004 parameters, and the widespread use of multi-core CPUs. Key improvements include expanded tools for assessing RNA-RNA interactions, additional output information such as centroid structures and maximum expected accuracy structures, and support for Easta format input. The core algorithms remain efficient, and the package now supports concurrent computations via OpenMP. The ViennaRNA Package 2.0 is available for download and can be used for both research and practical applications in RNA bioinformatics.The ViennaRNA Package 2.0 is an updated version of the widely used software for RNA secondary structure prediction and analysis. This package has been extensively revised to incorporate major changes in the standard energy model, the Turner 2004 parameters, and the widespread use of multi-core CPUs. Key improvements include expanded tools for assessing RNA-RNA interactions, additional output information such as centroid structures and maximum expected accuracy structures, and support for Easta format input. The core algorithms remain efficient, and the package now supports concurrent computations via OpenMP. The ViennaRNA Package 2.0 is available for download and can be used for both research and practical applications in RNA bioinformatics.