diff --git a/sample_apps/esp32_c3_hello/alire.toml b/sample_apps/esp32_c3_hello/alire.toml
index 2d9ef88..8f9926d 100644
--- a/sample_apps/esp32_c3_hello/alire.toml
+++ b/sample_apps/esp32_c3_hello/alire.toml
@@ -12,6 +12,7 @@ executables = ["esp32_c3_hello"]
 hirtos = "*"
 gnat_riscv64_elf = "*"
 gnatprove = "*"
+gprbuild = "^22" # needed by alire-index CI builds
 
 [configuration.values]
 hirtos.Platform = "esp32_c3"
diff --git a/sample_apps/fvp_armv8r_aarch32_hello/alire.toml b/sample_apps/fvp_armv8r_aarch32_hello/alire.toml
index f566c37..7e24fe3 100644
--- a/sample_apps/fvp_armv8r_aarch32_hello/alire.toml
+++ b/sample_apps/fvp_armv8r_aarch32_hello/alire.toml
@@ -12,6 +12,7 @@ executables = ["fvp_armv8r_aarch32_hello"]
 hirtos = "*"
 gnat_arm_elf = "*"
 gnatprove = "*"
+gprbuild = "^22" # needed by alire-index CI builds
 
 [[pins]]
 hirtos = { path='../..' }
diff --git a/sample_apps/hello_partitions/alire.toml b/sample_apps/hello_partitions/alire.toml
index 3133355..b159daf 100644
--- a/sample_apps/hello_partitions/alire.toml
+++ b/sample_apps/hello_partitions/alire.toml
@@ -14,6 +14,7 @@ executables = ["hello_partitions"]
 hirtos_separation_kernel = "*"
 gnat_arm_elf = "*"
 gnatprove = "*"
+gprbuild = "^22" # needed by alire-index CI builds
 
 [[pins]]
 hirtos_separation_kernel = { path='../../hirtos_separation_kernel' }
diff --git a/sample_apps/hello_partitions/hello_partition1/alire.toml b/sample_apps/hello_partitions/hello_partition1/alire.toml
index 4a9a0fb..8318db5 100644
--- a/sample_apps/hello_partitions/hello_partition1/alire.toml
+++ b/sample_apps/hello_partitions/hello_partition1/alire.toml
@@ -11,6 +11,7 @@ executables = ["hello_partition1"]
 [[depends-on]]
 hirtos = "*"
 gnat_arm_elf = "*"
+gprbuild = "^22" # needed by alire-index CI builds
 
 [[pins]]
 hirtos = { path='../../..' }
diff --git a/sample_apps/hello_partitions/hello_partition2/alire.toml b/sample_apps/hello_partitions/hello_partition2/alire.toml
index 1c924cb..52df8a7 100644
--- a/sample_apps/hello_partitions/hello_partition2/alire.toml
+++ b/sample_apps/hello_partitions/hello_partition2/alire.toml
@@ -11,6 +11,7 @@ executables = ["hello_partition2"]
 [[depends-on]]
 hirtos = "*"
 gnat_arm_elf = "*"
+gprbuild = "^22" # needed by alire-index CI builds
 
 [[pins]]
 hirtos = { path='../../..' }