Description of problem:
Just upgrade to Fedora 25, brought up Fedora's version of Eclipse...

Version-Release number of selected component:
eclipse-mylyn-3.20.2-1.fc25

Additional info:
reporter:       libreport-2.8.0
cmdline:        /usr/bin/java -Dosgi.requiredJavaVersion=1.8 -Xms128m -Xmx1024m -Dorg.eclipse.swt.browser.UseWebKitGTK=true -Dhelp.lucene.tokenizer=standard -XX:CompileCommand=exclude,org/eclipse/core/internal/dtree/DataTreeNode,forwardDeltaWith -XX:CompileCommand=exclude,org/eclipse/jdt/internal/compiler/lookup/ParameterizedMethodBinding,<init> -XX:CompileCommand=exclude,org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/CPPTemplates,instantiateTemplate -XX:CompileCommand=exclude,org/eclipse/cdt/internal/core/pdom/dom/cpp/PDOMCPPLinkage,addBinding -XX:CompileCommand=exclude,org/python/pydev/editor/codecompletion/revisited/PythonPathHelper,isValidSourceFile -XX:CompileCommand=exclude,org/eclipse/tycho/core/osgitools/EquinoxResolver,newState -Dorg.eclipse.equinox.p2.reconciler.dropins.directory=/usr/share/eclipse/dropins -Dp2.fragments=/usr/share/eclipse/droplets,/usr/lib64/eclipse/droplets -Declipse.p2.skipMovedInstallDetection=true -jar /usr/lib64/eclipse//plugins/org.eclipse.equinox.launcher_1.3.200.v20160915-0852.jar -os linux -ws gtk -arch x86_64 -showsplash /usr/lib64/eclipse//plugins/org.eclipse.platform_4.6.1.v20160915-0852/splash.bmp -launcher /usr/lib64/eclipse/eclipse -name Eclipse --launcher.library /usr/lib64/eclipse//plugins/org.eclipse.equinox.launcher.gtk.linux.x86_64_1.1.400.v20160915-0852/eclipse_1617.so -startup /usr/lib64/eclipse//plugins/org.eclipse.equinox.launcher_1.3.200.v20160915-0852.jar -protect master --launcher.appendVmargs -exitdata b348015 -vm /usr/bin/java -vmargs -Dosgi.requiredJavaVersion=1.8 -Xms128m -Xmx1024m -Dorg.eclipse.swt.browser.UseWebKitGTK=true -Dhelp.lucene.tokenizer=standard -XX:CompileCommand=exclude,org/eclipse/core/internal/dtree/DataTreeNode,forwardDeltaWith -XX:CompileCommand=exclude,org/eclipse/jdt/internal/compiler/lookup/ParameterizedMethodBinding,<init> -XX:CompileCommand=exclude,org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/CPPTemplates,instantiateTemplate -XX:CompileCommand=exclude,org/eclipse/cdt/internal/core/pdom/dom/cpp/PDOMCPPLinkage,addBinding -XX:CompileCommand=exclude,org/python/pydev/editor/codecompletion/revisited/PythonPathHelper,isValidSourceFile -XX:CompileCommand=exclude,org/eclipse/tycho/core/osgitools/EquinoxResolver,newState -Dorg.eclipse.equinox.p2.reconciler.dropins.directory=/usr/share/eclipse/dropins -Dp2.fragments=/usr/share/eclipse/droplets,/usr/lib64/eclipse/droplets -Declipse.p2.skipMovedInstallDetection=true -jar /usr/lib64/eclipse//plugins/org.eclipse.equinox.launcher_1.3.200.v20160915-0852.jar
eclipseplugin:  org.eclipse.mylyn.tasks.index.core
executable:     /usr/share/eclipse/droplets/mylyn-commons/eclipse/plugins/org.eclipse.mylyn.tasks.index.core_3.20.2.v20160803-1222.jar
kernel:         4.8.6-300.fc25.x86_64
pkg_fingerprint: 4089 D8F2 FDB1 9C98
pkg_vendor:     Fedora Project
runlevel:       N 5
type:           libreport
uid:            1000

Truncated backtrace:
org.eclipse.core.runtime.CoreException: Unexpected exception: Format version is not supported (resource BufferedChecksumIndexInput(NIOFSIndexInput(path="/home/gavin/AAA/myprojects/eclipse/ws-3-html-angularjs/.metadata/.mylyn/.taskListIndex/segments_1"))): -11 (needs to be between 1071082519 and 1071082519). This version of Lucene only supports indexes created with release 4.0 and later.
	at org.eclipse.mylyn.internal.tasks.index.core.TaskListIndex.maintainIndex(TaskListIndex.java:1099)
	at org.eclipse.mylyn.internal.tasks.index.core.TaskListIndex.access$0(TaskListIndex.java:1066)
	at org.eclipse.mylyn.internal.tasks.index.core.TaskListIndex$MaintainIndexJob.run(TaskListIndex.java:183)
	at org.eclipse.core.internal.jobs.Worker.run(Worker.java:55)
Caused by: org.apache.lucene.index.IndexFormatTooOldException: Format version is not supported (resource BufferedChecksumIndexInput(NIOFSIndexInput(path="/home/gavin/AAA/myprojects/eclipse/ws-3-html-angularjs/.metadata/.mylyn/.taskListIndex/segments_1"))): -11 (needs to be between 1071082519 and 1071082519). This version of Lucene only supports indexes created with release 4.0 and later.
	at org.apache.lucene.index.SegmentInfos.readCommit(SegmentInfos.java:299)
	at org.apache.lucene.index.IndexWriter.<init>(IndexWriter.java:910)
	at org.eclipse.mylyn.internal.tasks.index.core.TaskListIndex.createIndexWriter(TaskListIndex.java:1274)
	at org.eclipse.mylyn.internal.tasks.index.core.TaskListIndex.rebuildIndexCompletely(TaskListIndex.java:1217)
	at org.eclipse.mylyn.internal.tasks.index.core.TaskListIndex.maintainIndex(TaskListIndex.java:1085)
	... 3 more