This release of POI 4 XPages focuses primarily on moving from POI 3.x to the current version, 5.1. Internally, it bumps the dependencies and adapts to the changed API through the several intervening major versions. The existing additional capabilities built on top of the core POI API - the XPages controls, etc. - should work as they did before. It requires Java 8, and so targets 9.0.1FP10 and above.

Since the structure of the plugins changed noticeably between versions, the safest way to upgrade would be to fully remove the old version from your client or server before installing this version.

Existing apps may need code changes if they used the POI API directly, as several components changed in incompatible ways. Most of these changes involve moving from int-based constants to enums and are fairly straightforward to adapt to, but some are a little more esoteric. The amount of work involved will depend on the complexity of your use of the POI API.

Note for Notes V11 and above: starting with V11, the Notes client includes POI version 4.x in its default classpath. While this appears to be largely API-compatible with 5.x and does not seem to impede basic use, it's possible that this classpath corruption will cause trouble during development. If so, it's likely that you can remove the poi-* JARs from jvm/lib/ext on a Designer installation, unless you happen to use whatever it is in Notes that expects them to be there.