diff --git a/library/TextBuilderDev.hs b/library/TextBuilderDev.hs
--- a/library/TextBuilderDev.hs
+++ b/library/TextBuilderDev.hs
@@ -218,47 +218,31 @@
         intervalInSeconds @Double <$> arbitrary
       ]
 
-instance IsSome TextBuilder Text where
+instance IsomorphicTo TextBuilder Text where
   to = TextBuilderDev.text
 
-instance IsSome Text TextBuilder where
+instance IsomorphicTo Text TextBuilder where
   to = TextBuilderDev.buildText
 
-instance Is Text TextBuilder
-
-instance Is TextBuilder Text
-
-instance IsSome TextBuilder TextLazy.Text where
+instance IsomorphicTo TextBuilder TextLazy.Text where
   to = TextBuilderDev.lazyText
 
-instance IsSome TextLazy.Text TextBuilder where
+instance IsomorphicTo TextLazy.Text TextBuilder where
   to = to . to @Text
 
-instance Is TextLazy.Text TextBuilder
-
-instance Is TextBuilder TextLazy.Text
-
-instance IsSome TextBuilder TextLazyBuilder.Builder where
+instance IsomorphicTo TextBuilder TextLazyBuilder.Builder where
   to = to . to @TextLazy.Text
 
-instance IsSome TextLazyBuilder.Builder TextBuilder where
+instance IsomorphicTo TextLazyBuilder.Builder TextBuilder where
   to = to . to @Text
 
-instance Is TextLazyBuilder.Builder TextBuilder
-
-instance Is TextBuilder TextLazyBuilder.Builder
-
 #if MIN_VERSION_text(2,0,2)
 
-instance IsSome TextBuilder TextEncoding.StrictBuilder where
+instance IsomorphicTo TextBuilder TextEncoding.StrictBuilder where
   to = to . TextEncoding.strictBuilderToText
 
-instance IsSome TextEncoding.StrictBuilder TextBuilder where
+instance IsomorphicTo TextEncoding.StrictBuilder TextBuilder where
   to = TextEncoding.textToStrictBuilder . to
-
-instance Is TextBuilder TextEncoding.StrictBuilder
-
-instance Is TextEncoding.StrictBuilder TextBuilder
 
 #endif
 -- * Accessors
diff --git a/text-builder-dev.cabal b/text-builder-dev.cabal
--- a/text-builder-dev.cabal
+++ b/text-builder-dev.cabal
@@ -1,6 +1,6 @@
 cabal-version: 3.0
 name: text-builder-dev
-version: 0.3.7
+version: 0.3.8
 category: Text, Builders
 synopsis: Edge of developments for "text-builder"
 description:
@@ -81,7 +81,7 @@
     base >=4.11 && <5,
     bytestring >=0.10 && <0.13,
     deferred-folds >=0.9.10.1 && <0.10,
-    isomorphism-class >=0.2.1.1 && <0.3,
+    isomorphism-class >=0.3 && <0.4,
     quickcheck-instances >=0.3.28 && <0.4,
     split >=0.2.3.4 && <0.3,
     text >=1.0 && <3,