diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index e75f27da..f64f7eb2 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -22,6 +22,10 @@ jobs:
         exclude:
           - os: macOS-latest
             arch: x86
+        include:
+          - os: ubuntu-latest
+            arch: x64
+            version: '1.6'
     steps:
       - uses: actions/checkout@v4
       - uses: julia-actions/setup-julia@v1
diff --git a/Project.toml b/Project.toml
index 4ca150fc..56f8ab0a 100644
--- a/Project.toml
+++ b/Project.toml
@@ -24,7 +24,7 @@ LRUCache = "1"
 QuantumInterface = "0.3.0"
 Strided = "1, 2"
 UnsafeArrays = "1"
-julia = "1.3"
+julia = "1.6"
 
 [extras]
 Adapt = "79e6a3ab-5dfb-504d-930d-738a2a938a0e"
diff --git a/test/test_time_dependent_operators.jl b/test/test_time_dependent_operators.jl
index fbc4e664..29b4eaac 100644
--- a/test/test_time_dependent_operators.jl
+++ b/test/test_time_dependent_operators.jl
@@ -225,7 +225,7 @@ end
     op_stretch_block_shift = time_stretch(op_block_shift, 2.0)
     @test @inferred QOB.eval_coefficients(op_stretch_block_shift, 9.9) == (0.0, 0.0)
     @test @inferred QOB.eval_coefficients(op_stretch_block_shift, 10.0) == (1.0, -5.0)
-    @test @inferred QOB.eval_coefficients(op_stretch_block_shift, 30.0-√eps()) == (1.0, 5.0-0.5√eps())
+    @test @inferred QOB.eval_coefficients(op_stretch_block_shift, 30.0-√eps()) == (1.0, 5.0-0.5*√eps())
     @test @inferred QOB.eval_coefficients(op_stretch_block_shift, 30.0) == (0.0, 0.0)
 
     op_block = time_restrict(op, 15.0)