diff --git a/network/ports/ctlplane_vip.yaml b/network/ports/ctlplane_vip.yaml
index 7a7043bd60..1d8b29167d 100644
--- a/network/ports/ctlplane_vip.yaml
+++ b/network/ports/ctlplane_vip.yaml
@@ -1,4 +1,4 @@
-heat_template_version: 2015-04-30
+heat_template_version: 2015-10-15
 
 description: >
   Creates a port for a VIP on the undercloud ctlplane network.
@@ -46,12 +46,10 @@ outputs:
     description: Virtual IP network IP
     value: {get_attr: [VipPort, fixed_ips, 0, ip_address]}
   ip_subnet:
-    # FIXME: this assumes a 2 digit subnet CIDR (need more heat functions?)
     description: IP/Subnet CIDR for the ctlplane network.
     value:
           list_join:
             - ''
             - - {get_attr: [VipPort, fixed_ips, 0, ip_address]}
               - '/'
-              - {get_attr: [VipPort, subnets, 0, cidr, -2]}
-              - {get_attr: [VipPort, subnets, 0, cidr, -1]}
+              - {str_split: ['/', {get_attr: [VipPort, subnets, 0, cidr]}, 1]}
diff --git a/network/ports/external.yaml b/network/ports/external.yaml
index 7624eb9f84..df12cc8087 100644
--- a/network/ports/external.yaml
+++ b/network/ports/external.yaml
@@ -1,4 +1,4 @@
-heat_template_version: 2015-04-30
+heat_template_version: 2015-10-15
 
 description: >
   Creates a port on the external network. The IP address will be chosen
@@ -49,12 +49,10 @@ outputs:
     description: external network IP
     value: {get_attr: [ExternalPort, fixed_ips, 0, ip_address]}
   ip_subnet:
-    # FIXME: this assumes a 2 digit subnet CIDR (need more heat functions?)
     description: IP/Subnet CIDR for the external network IP
     value:
           list_join:
             - ''
             - - {get_attr: [ExternalPort, fixed_ips, 0, ip_address]}
               - '/'
-              - {get_attr: [ExternalPort, subnets, 0, cidr, -2]}
-              - {get_attr: [ExternalPort, subnets, 0, cidr, -1]}
+              - {str_split: ['/', {get_attr: [ExternalPort, subnets, 0, cidr]}, 1]}
diff --git a/network/ports/external_from_pool.yaml b/network/ports/external_from_pool.yaml
index 8e9dc7c207..5e61683adf 100644
--- a/network/ports/external_from_pool.yaml
+++ b/network/ports/external_from_pool.yaml
@@ -1,4 +1,4 @@
-heat_template_version: 2015-04-30
+heat_template_version: 2015-10-15
 
 description: >
   Returns an IP from a network mapped list of IPs
@@ -34,12 +34,10 @@ outputs:
     description: external network IP
     value: {get_param: [IPPool, {get_param: ExternalNetName}, {get_param: NodeIndex}]}
   ip_subnet:
-    # FIXME: this assumes a 2 digit subnet CIDR (need more heat functions?)
     description: IP/Subnet CIDR for the external network IP
     value:
       list_join:
       - ''
       - - {get_param: [IPPool, {get_param: ExternalNetName}, {get_param: NodeIndex}]}
         - '/'
-        - {get_param: [ExternalNetCidr, -2]}
-        - {get_param: [ExternalNetCidr, -1]}
+        - {str_split: ['/', {get_param: ExternalNetCidr}, 1]}
diff --git a/network/ports/internal_api.yaml b/network/ports/internal_api.yaml
index f84e8f7120..4039f9d7ef 100644
--- a/network/ports/internal_api.yaml
+++ b/network/ports/internal_api.yaml
@@ -1,4 +1,4 @@
-heat_template_version: 2015-04-30
+heat_template_version: 2015-10-15
 
 description: >
   Creates a port on the internal_api network.
@@ -44,12 +44,10 @@ outputs:
     description: internal API network IP
     value: {get_attr: [InternalApiPort, fixed_ips, 0, ip_address]}
   ip_subnet:
-    # FIXME: this assumes a 2 digit subnet CIDR (need more heat functions?)
     description: IP/Subnet CIDR for the internal API network IP
     value:
           list_join:
             - ''
             - - {get_attr: [InternalApiPort, fixed_ips, 0, ip_address]}
               - '/'
-              - {get_attr: [InternalApiPort, subnets, 0, cidr, -2]}
-              - {get_attr: [InternalApiPort, subnets, 0, cidr, -1]}
+              - {str_split: ['/', {get_attr: [InternalApiPort, subnets, 0, cidr]}, 1]}
diff --git a/network/ports/internal_api_from_pool.yaml b/network/ports/internal_api_from_pool.yaml
index b98e1fb1a0..18ccd2b212 100644
--- a/network/ports/internal_api_from_pool.yaml
+++ b/network/ports/internal_api_from_pool.yaml
@@ -1,4 +1,4 @@
-heat_template_version: 2015-04-30
+heat_template_version: 2015-10-15
 
 description: >
   Returns an IP from a network mapped list of IPs
@@ -34,12 +34,10 @@ outputs:
     description: internal API network IP
     value: {get_param: [IPPool, {get_param: InternalApiNetName}, {get_param: NodeIndex}]}
   ip_subnet:
-    # FIXME: this assumes a 2 digit subnet CIDR (need more heat functions?)
     description: IP/Subnet CIDR for the internal API network IP
     value:
       list_join:
       - ''
       - - {get_param: [IPPool, {get_param: InternalApiNetName}, {get_param: NodeIndex}]}
         - '/'
-        - {get_param: [InternalApiNetCidr, -2]}
-        - {get_param: [InternalApiNetCidr, -1]}
+        - {str_split: ['/', {get_param: InternalApiNetCidr}, 1]}
diff --git a/network/ports/management.yaml b/network/ports/management.yaml
index 1d15ca6020..20c1b8539b 100644
--- a/network/ports/management.yaml
+++ b/network/ports/management.yaml
@@ -1,4 +1,4 @@
-heat_template_version: 2015-04-30
+heat_template_version: 2015-10-15
 
 description: >
   Creates a port on the management network. The IP address will be chosen
@@ -31,12 +31,10 @@ outputs:
     description: management network IP
     value: {get_attr: [ManagementPort, fixed_ips, 0, ip_address]}
   ip_subnet:
-    # FIXME: this assumes a 2 digit subnet CIDR (need more heat functions?)
     description: IP/Subnet CIDR for the management network IP
     value:
           list_join:
             - ''
             - - {get_attr: [ManagementPort, fixed_ips, 0, ip_address]}
               - '/'
-              - {get_attr: [ManagementPort, subnets, 0, cidr, -2]}
-              - {get_attr: [ManagementPort, subnets, 0, cidr, -1]}
+              - {str_split: ['/', {get_attr: [ManagementPort, subnets, 0, cidr]}, 1]}
diff --git a/network/ports/storage.yaml b/network/ports/storage.yaml
index a07e5a4f93..579554fb58 100644
--- a/network/ports/storage.yaml
+++ b/network/ports/storage.yaml
@@ -1,4 +1,4 @@
-heat_template_version: 2015-04-30
+heat_template_version: 2015-10-15
 
 description: >
   Creates a port on the storage network.
@@ -44,12 +44,10 @@ outputs:
     description: storage network IP
     value: {get_attr: [StoragePort, fixed_ips, 0, ip_address]}
   ip_subnet:
-    # FIXME: this assumes a 2 digit subnet CIDR (need more heat functions?)
     description: IP/Subnet CIDR for the storage network IP
     value:
           list_join:
             - ''
             - - {get_attr: [StoragePort, fixed_ips, 0, ip_address]}
               - '/'
-              - {get_attr: [StoragePort, subnets, 0, cidr, -2]}
-              - {get_attr: [StoragePort, subnets, 0, cidr, -1]}
+              - {str_split: ['/', {get_attr: [StoragePort, subnets, 0, cidr]}, 1]}
diff --git a/network/ports/storage_from_pool.yaml b/network/ports/storage_from_pool.yaml
index 668bc6f692..13c16c15bf 100644
--- a/network/ports/storage_from_pool.yaml
+++ b/network/ports/storage_from_pool.yaml
@@ -1,4 +1,4 @@
-heat_template_version: 2015-04-30
+heat_template_version: 2015-10-15
 
 description: >
   Returns an IP from a network mapped list of IPs
@@ -34,12 +34,10 @@ outputs:
     description: storage network IP
     value: {get_param: [IPPool, {get_param: StorageNetName}, {get_param: NodeIndex}]}
   ip_subnet:
-    # FIXME: this assumes a 2 digit subnet CIDR (need more heat functions?)
     description: IP/Subnet CIDR for the storage network IP
     value:
       list_join:
       - ''
       - - {get_param: [IPPool, {get_param: StorageNetName}, {get_param: NodeIndex}]}
         - '/'
-        - {get_param: [StorageNetCidr, -2]}
-        - {get_param: [StorageNetCidr, -1]}
+        - {str_split: ['/', {get_param: StorageNetCidr}, 1]}
diff --git a/network/ports/storage_mgmt.yaml b/network/ports/storage_mgmt.yaml
index 4890bf5a9e..f97e337b88 100644
--- a/network/ports/storage_mgmt.yaml
+++ b/network/ports/storage_mgmt.yaml
@@ -1,4 +1,4 @@
-heat_template_version: 2015-04-30
+heat_template_version: 2015-10-15
 
 description: >
   Creates a port on the storage_mgmt API network.
@@ -44,12 +44,10 @@ outputs:
     description: storage_mgmt network IP
     value: {get_attr: [StorageMgmtPort, fixed_ips, 0, ip_address]}
   ip_subnet:
-    # FIXME: this assumes a 2 digit subnet CIDR (need more heat functions?)
     description: IP/Subnet CIDR for the storage_mgmt network IP
     value:
           list_join:
             - ''
             - - {get_attr: [StorageMgmtPort, fixed_ips, 0, ip_address]}
               - '/'
-              - {get_attr: [StorageMgmtPort, subnets, 0, cidr, -2]}
-              - {get_attr: [StorageMgmtPort, subnets, 0, cidr, -1]}
+              - {str_split: ['/', {get_attr: [StorageMgmtPort, subnets, 0, cidr]}, 1]}
diff --git a/network/ports/storage_mgmt_from_pool.yaml b/network/ports/storage_mgmt_from_pool.yaml
index bea8710599..7c033ebd8e 100644
--- a/network/ports/storage_mgmt_from_pool.yaml
+++ b/network/ports/storage_mgmt_from_pool.yaml
@@ -1,4 +1,4 @@
-heat_template_version: 2015-04-30
+heat_template_version: 2015-10-15
 
 description: >
   Returns an IP from a network mapped list of IPs
@@ -34,12 +34,10 @@ outputs:
     description: storage MGMT network IP
     value: {get_param: [IPPool, {get_param: StorageMgmtNetName}, {get_param: NodeIndex}]}
   ip_subnet:
-    # FIXME: this assumes a 2 digit subnet CIDR (need more heat functions?)
     description: IP/Subnet CIDR for the storage MGMT network IP
     value:
       list_join:
       - ''
       - - {get_param: [IPPool, {get_param: StorageMgmtNetName}, {get_param: NodeIndex}]}
         - '/'
-        - {get_param: [StorageMgmtNetCidr, -2]}
-        - {get_param: [StorageMgmtNetCidr, -1]}
+        - {str_split: ['/', {get_param: StorageMgmtNetCidr}, 1]}
diff --git a/network/ports/tenant.yaml b/network/ports/tenant.yaml
index 86c58f2f12..cc0771eaad 100644
--- a/network/ports/tenant.yaml
+++ b/network/ports/tenant.yaml
@@ -1,4 +1,4 @@
-heat_template_version: 2015-04-30
+heat_template_version: 2015-10-15
 
 description: >
   Creates a port on the tenant network.
@@ -44,12 +44,10 @@ outputs:
     description: tenant network IP
     value: {get_attr: [TenantPort, fixed_ips, 0, ip_address]}
   ip_subnet:
-    # FIXME: this assumes a 2 digit subnet CIDR (need more heat functions?)
     description: IP/Subnet CIDR for the tenant network IP
     value:
           list_join:
             - ''
             - - {get_attr: [TenantPort, fixed_ips, 0, ip_address]}
               - '/'
-              - {get_attr: [TenantPort, subnets, 0, cidr, -2]}
-              - {get_attr: [TenantPort, subnets, 0, cidr, -1]}
+              - {str_split: ['/', {get_attr: [TenantPort, subnets, 0, cidr]}, 1]}
diff --git a/network/ports/tenant_from_pool.yaml b/network/ports/tenant_from_pool.yaml
index 29303bb69d..17e4ac8ab3 100644
--- a/network/ports/tenant_from_pool.yaml
+++ b/network/ports/tenant_from_pool.yaml
@@ -1,4 +1,4 @@
-heat_template_version: 2015-04-30
+heat_template_version: 2015-10-15
 
 description: >
   Returns an IP from a network mapped list of IPs
@@ -34,12 +34,10 @@ outputs:
     description: tenant network IP
     value: {get_param: [IPPool, {get_param: TenantNetName}, {get_param: NodeIndex}]}
   ip_subnet:
-    # FIXME: this assumes a 2 digit subnet CIDR (need more heat functions?)
     description: IP/Subnet CIDR for the tenant network IP
     value:
       list_join:
       - ''
       - - {get_param: [IPPool, {get_param: TenantNetName}, {get_param: NodeIndex}]}
         - '/'
-        - {get_param: [TenantNetCidr, -2]}
-        - {get_param: [TenantNetCidr, -1]}
+        - {str_split: ['/', {get_param: TenantNetCidr}, 1]}
diff --git a/network/ports/vip.yaml b/network/ports/vip.yaml
index 9bb6cde26b..fb25199456 100644
--- a/network/ports/vip.yaml
+++ b/network/ports/vip.yaml
@@ -1,4 +1,4 @@
-heat_template_version: 2015-04-30
+heat_template_version: 2015-10-15
 
 description: >
   Creates a port for a VIP on the isolated network NetworkName.
@@ -46,12 +46,10 @@ outputs:
     description: Virtual IP network IP
     value: {get_attr: [VipPort, fixed_ips, 0, ip_address]}
   ip_subnet:
-    # FIXME: this assumes a 2 digit subnet CIDR (need more heat functions?)
     description: IP/Subnet CIDR for the network associated with this IP
     value:
           list_join:
             - ''
             - - {get_attr: [VipPort, fixed_ips, 0, ip_address]}
               - '/'
-              - {get_attr: [VipPort, subnets, 0, cidr, -2]}
-              - {get_attr: [VipPort, subnets, 0, cidr, -1]}
+              - {str_split: ['/', {get_attr: [VipPort, subnets, 0, cidr]}, 1]}