diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,5 +1,10 @@
 # Changelog for srtree
 
+## 2.0.1.5
+
+- Fix `refit` to only replace the fitness if it improves the fitness 
+- Fix `paretoFront` 
+
 ## 2.0.1.4
 
 - Added `loadTrainingOnly`, `splitData`, and `loadX` to `Data.SRTree.Datasets`
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -7,9 +7,9 @@
 - [srsimplify](apps/srsimplify/README.md): a parser and simplification tool supporting the output of many popular SR algorithms.
 - [srtools](apps/srtools/README.md): a tool that can be used to evaluate symbolic regression expressions and create nice reports with confidence intervals. 
 - [tinygp](apps/tinygp/README.md): a simple GP implementation based on tinyGP.
-- [rEGGression](apps/rEGGression/README.md): nonlinear regression models exploration and query system with e-graphs (egg).
-- [symregg](apps/symregg/README.md): Equality graph Assisted Search Technique for Equation Recovery.
-- [eggp](apps/eggp/README.md): E-graph Genetic Programming.
+- [rEGGression](https://github.com/folivetti/reggression/blob/main/README.md): nonlinear regression models exploration and query system with e-graphs (egg).
+- [symregg](https://github.com/folivetti/symregg/blob/main/README.md): Equality graph Assisted Search Technique for Equation Recovery.
+- [eggp](https://github.com/folivetti/eggp/blob/main/README.md): E-graph Genetic Programming.
 
 ## SRTree
 
diff --git a/src/Algorithm/EqSat.hs b/src/Algorithm/EqSat.hs
--- a/src/Algorithm/EqSat.hs
+++ b/src/Algorithm/EqSat.hs
@@ -122,7 +122,7 @@
                        -- step 1: match the rules
                        let matchSch        = matchWithScheduler it
                            matchAll        = zipWithM matchSch [0..]
-                           (rules, sch') = runState (matchAll rules') sch
+                           (rules, sch')   = runState (matchAll rules') sch
 
                        -- step 2: apply matches and rebuild
                        matches <- mapM (\rule -> map (rule,) <$> match (source rule)) $ concat rules
diff --git a/src/Algorithm/EqSat/SearchSR.hs b/src/Algorithm/EqSat/SearchSR.hs
--- a/src/Algorithm/EqSat/SearchSR.hs
+++ b/src/Algorithm/EqSat/SearchSR.hs
@@ -145,7 +145,10 @@
 refit fitFun ec = do
   t <- getBestExpr ec
   (f, p) <- fitFun t
-  insertFitness ec f p
+  mf <- getFitness ec
+  case mf of
+    Nothing -> insertFitness ec f p
+    Just f' -> when (f > f') $ insertFitness ec f p
 
 --printBest :: (Int -> EClassId -> RndEGraph ()) -> RndEGraph ()
 printBest fitFun printExprFun = do
@@ -166,14 +169,14 @@
             if not (null ecList)
                 then do let (ec, mf) = head ecList
                             f' = fromJust mf
-                            improved = f' > f && (not . isNaN) f' && (not . isInfinite) f'
+                            improved = f' >= f && (not . isNaN) f' && (not . isInfinite) f'
                         ec' <- canonical ec
                         if improved
                                 then do refit fitFun ec'
                                         t <- printExprFun ix ec'
-                                        ts <- go (n+1) (ix + if improved then 1 else 0) (max f (fromJust mf))
+                                        ts <- go (n+1) (ix + if improved then 1 else 0) (max f f')
                                         pure (t:ts)
-                                else go (n+1) (ix + if improved then 1 else 0) (max f (fromJust mf))
+                                else go (n+1) (ix + if improved then 1 else 0) (max f f')
                 else go (n+1) ix f
 
 evaluateUnevaluated fitFun = do
diff --git a/srtree.cabal b/srtree.cabal
--- a/srtree.cabal
+++ b/srtree.cabal
@@ -5,7 +5,7 @@
 -- see: https://github.com/sol/hpack
 
 name:           srtree
-version:        2.0.1.4
+version:        2.0.1.5
 synopsis:       A general library to work with Symbolic Regression expression trees.
 description:    A Symbolic Regression Tree data structure to work with mathematical expressions with support to first order derivative and simplification;
 category:       Math, Data, Data Structures
@@ -111,7 +111,7 @@
     , list-shuffle >=1.0.0.1 && <1.1
     , massiv >=1.0.4.1 && <1.1
     , mtl >=2.2 && <2.4
-    , optparse-applicative >=0.17 && <0.19
+    , optparse-applicative >=0.18 && <0.20
     , random >=1.2 && <1.4
     , scheduler >=2.0.0.1 && <3
     , split >=0.2.5 && <0.3
@@ -151,7 +151,7 @@
     , list-shuffle >=1.0.0.1 && <1.1
     , massiv >=1.0.4.1 && <1.1
     , mtl >=2.2 && <2.4
-    , optparse-applicative >=0.17 && <0.19
+    , optparse-applicative >=0.18 && <0.20
     , random >=1.2 && <1.4
     , scheduler >=2.0.0.1 && <3
     , split >=0.2.5 && <0.3
@@ -191,7 +191,7 @@
     , list-shuffle >=1.0.0.1 && <1.1
     , massiv >=1.0.4.1 && <1.1
     , mtl >=2.2 && <2.4
-    , optparse-applicative >=0.17 && <0.19
+    , optparse-applicative >=0.18 && <0.20
     , random >=1.2 && <1.4
     , scheduler >=2.0.0.1 && <3
     , split >=0.2.5 && <0.3