since Solr 8.6 the version of tika-parsers was updated to 1.24. This version of tika-parsers needs the poi library in version 4.1.2 (see https://issues.apache.org/jira/browse/TIKA-3047)
Solr has version 4.1.1 of poi included.
This creates (at least) a problem for parsing .xls files. The following exception gets thrown by trying to post an .xls file in the techproducts example: