diff --git a/CHANGELOG.md b/CHANGELOG.md
index c4d3b93e9..fdace591c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,7 @@
 - Field extends ScaleOperations
 - Basic integration API
 - Basic MPP distributions and samplers
+- bindSymbolOrNull
 
 ### Changed
 - Exponential operations merged with hyperbolic functions
diff --git a/build.gradle.kts b/build.gradle.kts
index cc863a957..59e93e67f 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -18,7 +18,7 @@ allprojects {
     }
 
     group = "space.kscience"
-    version = "0.3.0-dev-4"
+    version = "0.3.0-dev-5"
 }
 
 subprojects {
diff --git a/kmath-kotlingrad/src/main/kotlin/space/kscience/kmath/kotlingrad/DifferentiableMstExpression.kt b/kmath-kotlingrad/src/main/kotlin/space/kscience/kmath/kotlingrad/DifferentiableMstExpression.kt
index d5b55e031..ab3547cda 100644
--- a/kmath-kotlingrad/src/main/kotlin/space/kscience/kmath/kotlingrad/DifferentiableMstExpression.kt
+++ b/kmath-kotlingrad/src/main/kotlin/space/kscience/kmath/kotlingrad/DifferentiableMstExpression.kt
@@ -5,7 +5,6 @@ import space.kscience.kmath.ast.MST
 import space.kscience.kmath.ast.MstAlgebra
 import space.kscience.kmath.ast.interpret
 import space.kscience.kmath.expressions.DifferentiableExpression
-import space.kscience.kmath.expressions.Expression
 import space.kscience.kmath.misc.Symbol
 import space.kscience.kmath.operations.NumericAlgebra
 
@@ -22,7 +21,7 @@ import space.kscience.kmath.operations.NumericAlgebra
 public class DifferentiableMstExpression<T : Number, A : NumericAlgebra<T>>(
     public val algebra: A,
     public val mst: MST,
-) : DifferentiableExpression<T, Expression<T>> {
+) : DifferentiableExpression<T, DifferentiableMstExpression<T, A>> {
 
     public override fun invoke(arguments: Map<Symbol, T>): T = mst.interpret(algebra, arguments)