Database schema

• The DATASET table now stores a mandatory isotope_id foreign key referencing the ISOTOPE table.
  • A dataset remains directly associated with its nucleus even when it contains no level.
  • Newly generated database histories can therefore attribute these datasets to their nucleus instead of grouping them under Unassigned.
• Databases generated with this schema use the v2.6 filename suffix, preventing them from being confused with databases using the 2.5 schema for the same ENSDF and XUNDL archives.

Physics API

• Spin and parity read accessors are now const-correct. Values returned by tknucleus::get_spin_parity() can be inspected directly without a const_cast.

Build and installation

• CMake 3.13 and C++17 are now required; the obsolete USE_CXX11 option has been removed.
• Installed libraries expose namespaced CMake targets such as tkn::tkphysics, allowing downstream projects to use find_package(TkN CONFIG REQUIRED) without global include or linker flags.
• Bash and Zsh completions are installed under their standard share/ directories. The thistkn.sh environment script registers them explicitly, including for installations under a non-system prefix.
• CMake configuration messages retain color for important information without overriding CMake's built-in message() command. Colors can be disabled with -DTKN_COLOR_OUTPUT=OFF or the NO_COLOR environment variable.

Database history

• New tkn-db-history command to compare successive published TkN databases and generate the database history data.
• The documentation now includes a database history page with:
  • separate ENSDF and XUNDL counts for datasets, levels and transitions;
  • additions, removals and modifications;
  • expandable details by nucleus, dataset, level and transition;
  • releases grouped by year;
  • the previous database used for each comparison and the corresponding ENSDF, XUNDL and TkN versions.
• Existing database branches reported by tkn-db-update --show can be used to reconstruct the history of earlier releases.
• A nucleus search on the main history page shows its latest data addition, recorded change, and ENSDF/XUNDL archive updates, followed by a release-by-release timeline linked to the detailed reports. Comment-only modifications can be hidden and are ignored by default.