What version of Luke is able to read 5.5.5 lucene's indexes? I've tried with Luke 4.10, 5.2, 5.5, 7.2 but always get this:
Invalid directory at the location, check console for more information. Last exception:
org.apache.lucene.index.IndexFormatTooOldException: Format version is not supported (resource BufferedChecksumIndexInput(MMapIndexInput(path=""))): this index is too old (version: 5.5.5). This version of Lucene only supports indexes created with release 6.0 and later.
We also use Lucene 5.5.5 for our project.
The latest version of Luke which supports it is 6.6.0 - https://github.com/DmitryKey/luke/releases/tag/luke-6.6.0