diff --git a/examples/3-parametric-heteroscedastic/Project.toml b/examples/3-parametric-heteroscedastic/Project.toml
index f62fe06f..a072a0ec 100644
--- a/examples/3-parametric-heteroscedastic/Project.toml
+++ b/examples/3-parametric-heteroscedastic/Project.toml
@@ -16,6 +16,6 @@ AbstractGPsMakie = "0.2"
 CairoMakie = "0.7 - 0.15"
 KernelFunctions = "0.10"
 Literate = "2"
-Optim = "1"
+Optim = "1, 2"
 ParameterHandling = "0.4, 0.5"
 Zygote = "0.6, 0.7"