diff --git a/lib/DiscreteMeasures/ext/IntervalArithmeticExt.jl b/lib/DiscreteMeasures/ext/IntervalArithmeticExt.jl
index 62ae7ca..0b597f3 100644
--- a/lib/DiscreteMeasures/ext/IntervalArithmeticExt.jl
+++ b/lib/DiscreteMeasures/ext/IntervalArithmeticExt.jl
@@ -1,11 +1,12 @@
 module IntervalArithmeticExt
 
-using DiscreteMeasures, IntervalArithmetic
+using DiscreteMeasures: DiscreteMeasures, clamp_domain
+using IntervalArithmetic: IntervalArithmetic, Interval, interval, intersect_interval
 
 println("Load Ext")
 function DiscreteMeasures.clamp_domain(x::Interval, lb, ub)
     bounds = interval(lb, ub)
-    return intersect(x, bounds)
+    return intersect_interval(x, bounds)
 end
 
 function DiscreteMeasures.clamp_weight(w::Interval{T}, maxw::T = one(T)) where {T}
diff --git a/lib/DiscreteMeasures/test/Core/discrete_measures_tests.jl b/lib/DiscreteMeasures/test/Core/discrete_measures_tests.jl
index 14a48ab..8f9febb 100644
--- a/lib/DiscreteMeasures/test/Core/discrete_measures_tests.jl
+++ b/lib/DiscreteMeasures/test/Core/discrete_measures_tests.jl
@@ -91,11 +91,13 @@ end
     end
 
     @testset "Interval Ext" begin
-        @test clamp_domain(interval(-2, -1), 0, 2) == emptyinterval()
-        @test clamp_domain(interval(-2, 1), 0, 2) == interval(0, 1)
-        @test clamp_domain(interval(0.1, 0.5), 0, 2) == interval(0.1, 0.5)
-        @test clamp_domain(interval(0.5, 5), 0, 2) == interval(0.5, 2)
-        @test clamp_domain(interval(3, 4), 0, 2) == emptyinterval()
+        # IntervalArithmetic 1.x: use isequal_interval — `==` on non-thin
+        # decorated intervals throws InconclusiveBooleanOperation.
+        @test isequal_interval(clamp_domain(interval(-2, -1), 0, 2), emptyinterval())
+        @test isequal_interval(clamp_domain(interval(-2, 1), 0, 2), interval(0, 1))
+        @test isequal_interval(clamp_domain(interval(0.1, 0.5), 0, 2), interval(0.1, 0.5))
+        @test isequal_interval(clamp_domain(interval(0.5, 5), 0, 2), interval(0.5, 2))
+        @test isequal_interval(clamp_domain(interval(3, 4), 0, 2), emptyinterval())
     end
 
 end