Undocumented nessesary of lucene-backward-codecs.jar in 1.31.3?

para 1.31.3 reports an error as below:

2019-06-06 21:31:21 [ERROR] null
java.lang.IllegalArgumentException: Could not load codec 'Lucene70'.  Did you forget to add lucene-backward-codecs.jar?
	at org.apache.lucene.index.SegmentInfos.readCodec(SegmentInfos.java:420)
	at org.apache.lucene.index.SegmentInfos.readCommit(SegmentInfos.java:352)
	at org.apache.lucene.index.SegmentInfos.readCommit(SegmentInfos.java:289)
	at org.apache.lucene.index.StandardDirectoryReader$1.doBody(StandardDirectoryReader.java:64)
	at org.apache.lucene.index.StandardDirectoryReader$1.doBody(StandardDirectoryReader.java:61)
	at org.apache.lucene.index.SegmentInfos$FindSegmentsFile.run(SegmentInfos.java:680)
	at org.apache.lucene.index.StandardDirectoryReader.open(StandardDirectoryReader.java:84)
	at org.apache.lucene.index.DirectoryReader.open(DirectoryReader.java:76)
	at org.apache.lucene.index.DirectoryReader.open(DirectoryReader.java:64)
	at com.erudika.para.search.LuceneUtils.getIndexReader(LuceneUtils.java:878)
	at com.erudika.para.search.LuceneUtils.searchQuery(LuceneUtils.java:719)
	at com.erudika.para.search.LuceneSearch.findById(LuceneSearch.java:155)
	at com.erudika.para.search.LuceneSearch$$EnhancerByGuice$$5b51948d.CGLIB$findById$21(<generated>)
	at com.erudika.para.search.LuceneSearch$$EnhancerByGuice$$5b51948d$$FastClassByGuice$$4f525818.invoke(<generated>)
	at com.google.inject.internal.cglib.proxy.$MethodProxy.invokeSuper(MethodProxy.java:228)
	at com.google.inject.internal.InterceptorStackCallback$InterceptedMethodInvocation.proceed(InterceptorStackCallback.java:76)
	at com.erudika.para.aop.SearchQueryAspect.invokeTimedSearch(SearchQueryAspect.java:93)
	at com.erudika.para.aop.SearchQueryAspect.invoke(SearchQueryAspect.java:78)
	at com.google.inject.internal.InterceptorStackCallback$InterceptedMethodInvocation.proceed(InterceptorStackCallback.java:78)
	at com.google.inject.internal.InterceptorStackCallback.intercept(InterceptorStackCallback.java:54)
	at com.erudika.para.search.LuceneSearch$$EnhancerByGuice$$5b51948d.findById(<generated>)
	at com.erudika.para.search.LuceneSearch.findById(LuceneSearch.java:375)
	at com.erudika.para.search.LuceneSearch$$EnhancerByGuice$$5b51948d.CGLIB$findById$20(<generated>)
	at com.erudika.para.search.LuceneSearch$$EnhancerByGuice$$5b51948d$$FastClassByGuice$$4f525818.invoke(<generated>)
	at com.google.inject.internal.cglib.proxy.$MethodProxy.invokeSuper(MethodProxy.java:228)
	at com.google.inject.internal.InterceptorStackCallback$InterceptedMethodInvocation.proceed(InterceptorStackCallback.java:76)
	at com.erudika.para.aop.SearchQueryAspect.invoke(SearchQueryAspect.java:80)
	at com.google.inject.internal.InterceptorStackCallback$InterceptedMethodInvocation.proceed(InterceptorStackCallback.java:78)
	at com.google.inject.internal.InterceptorStackCallback.intercept(InterceptorStackCallback.java:54)
	at com.erudika.para.search.LuceneSearch$$EnhancerByGuice$$5b51948d.findById(<generated>)
	at com.erudika.para.utils.HealthUtils$1.performHealthCheck(HealthUtils.java:65)
	at com.erudika.para.utils.HealthUtils$1.onInitialize(HealthUtils.java:93)
	at com.erudika.para.Para.initialize(Para.java:110)
	at com.erudika.para.ParaServer.initialize(ParaServer.java:153)
	at com.erudika.para.ParaServer.runAsJAR(ParaServer.java:415)
	at com.erudika.para.ParaServer.main(ParaServer.java:424)
	at com.erudika.para.Run.main(Run.java:26)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:48)
	at org.springframework.boot.loader.Launcher.launch(Launcher.java:87)
	at org.springframework.boot.loader.Launcher.launch(Launcher.java:50)
	at org.springframework.boot.loader.PropertiesLauncher.main(PropertiesLauncher.java:593)
Caused by: java.lang.IllegalArgumentException: An SPI class of type org.apache.lucene.codecs.Codec with name 'Lucene70' does not exist.  You need to add the corresponding JAR file supporting this SPI to your classpath.  The current classpath supports the following names: [Lucene80]
	at org.apache.lucene.util.NamedSPILoader.lookup(NamedSPILoader.java:116)
	at org.apache.lucene.codecs.Codec.forName(Codec.java:116)
	at org.apache.lucene.index.SegmentInfos.readCodec(SegmentInfos.java:416)
	... 44 common frames omitted
2019-06-06 21:31:21 [WARN ] Server is unhealthy - the search index may be corrupted and may have to be rebuilt.

I installed lucense 8.1.1 and booted up para successfully, but please put it in the latest document.

[albogdano]

@weisjohn @katatunix Hm, I thought a full reindex would be enough… anyway I added backward-codecs to the para-search-lucene project to make such migrations easier. https://github.com/Erudika/para-search-lucene/commit/06e035b1755d82243639f3be9125b00c28b14e40

[albogdano]

Rebuilding the index should also fix this - POST /v1/_reindex http://paraio.org/docs/#053-api-reindex