ZK Spreadsheet, initiated in 2008 and having it’s first GA-released in 2009 was one of the very first Web spreadsheets. After supporting customers for more than 10 years, ZSS retired in 2020, and a faster and smarter spreadsheet KEIKAI picks up the baton.

Why Upgrade?

ZSS Retired
ZK Spreadsheet reached its end of support and a better and faster Keikai Spreadsheet is taking over.

Compared to ZK Spreadsheet, Keikai has the following key improvements:

  • performance boost: importing, filtering, formula parsing, sheet cloning, etc.
  • consumes less memory
  • modern look & feel
  • tablet/mobile browser support
  • more features like formula dependent/precedent trace, auto column resizing, easier toolbar customization etc.

The underlying ZK and 3rd party libraries are updated
ZK is the underlying framework used in Keikai

  • ZK Spreadsheet depended on ZK 8.0 or earlier, which was released 5 years ago or even earlier
  • new ZK versions contain updated 3rd libraries & their security fixes (ex. jQuery)
  • new ZK versions are optimized for latest browsers and web servers (ex. removing old IE, supporting new browser versions)

Upgrade Recommendation

  • Keikai version – we recommend you to use the latest stable version (as of now 5.7.0)
  • ZK version – in order to include the latest 3rd party security fixes, we recommend you to use the current latest stable branch (currently 9.5.x) or at least 9.1.0+

Major Changes & Upgrade Tips

ZSS -> Keikai Upgrade Tips

* Keikai is developed based on ZSS 3.9, no architectural change

* Server-side breaking change:
==> Package name changed from org.zkoss.zss –> io.keikai
==> Deprecated APIs removed (refer to the migration guide below)

* Other changes (should be transparent for app developers unless customized)
==> New importer, new formula parser, filtering and UI enhancements, formula optimization
==> Toolbar customization (new approach easier control from server side)
==> Other customization: review case by case

* Patched jars (if any, most likely bug fixes)
==> Check patch comments, and see what’s the related bug tracker number, and check if such bug has been fixed in a newer version of ZSS/Keikai

For detailed changes please visit the ZSS -> Keikai Migration Guide


ZK Upgrade Tips

Keikai EE (and ZK Spreadsheet EE) depends on ZK PE. If you were previously using ZK Spreadsheet, it is most likely that you have been using an older ZK version. In most cases, ZK 6, 7, or 8. As recommended above, we suggest you to use ZK 9.1 or later when migrating to Keikai Spreadsheet.

When upgrading the underlying ZK, you will notice that new defaults ( new default theme, new css flex calculation) are introduced. However in most cases, fallback settings for backwards compatibility are available. Please read the ZK Upgrade Tips to see major/breaking changes and how you can configure them to be compatible.

We are here for you

Need help? Contact us at [email protected] and let us know your current status and doubts, we are here to help.

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