Fix wording of state format stability node.

README

@@ -242,5 +242,5 @@ prevented, but can produce nonsense/unreadable results. Or it can save the day
 if you do want to mix different parameters (ex: you have some logs generated
 with %T, others with %D).
 
-It is unclear how stable saved state format will evolve. Be prepared to have
-to regenerate saved states if you upgrade APacheDEX.
+It is unclear how saved state format will evolve. Be prepared to have
+to regenerate saved states when you upgrade APacheDEX.