diff --git a/amazonka-cloudformation.cabal b/amazonka-cloudformation.cabal
--- a/amazonka-cloudformation.cabal
+++ b/amazonka-cloudformation.cabal
@@ -1,5 +1,5 @@
 name:                  amazonka-cloudformation
-version:               0.3.4
+version:               0.3.5
 synopsis:              Amazon CloudFormation SDK.
 homepage:              https://github.com/brendanhay/amazonka
 license:               OtherLicense
@@ -65,5 +65,5 @@
     other-modules:
 
     build-depends:
-          amazonka-core == 0.3.4.*
+          amazonka-core == 0.3.5.*
         , base          >= 4.7     && < 5
diff --git a/gen/Network/AWS/CloudFormation/CancelUpdateStack.hs b/gen/Network/AWS/CloudFormation/CancelUpdateStack.hs
--- a/gen/Network/AWS/CloudFormation/CancelUpdateStack.hs
+++ b/gen/Network/AWS/CloudFormation/CancelUpdateStack.hs
@@ -65,7 +65,7 @@
     { _cusStackName = p1
     }
 
--- | The name or the unique identifier associated with the stack.
+-- | The name or the unique stack ID that is associated with the stack.
 cusStackName :: Lens' CancelUpdateStack Text
 cusStackName = lens _cusStackName (\s a -> s { _cusStackName = a })
 
diff --git a/gen/Network/AWS/CloudFormation/CreateStack.hs b/gen/Network/AWS/CloudFormation/CreateStack.hs
--- a/gen/Network/AWS/CloudFormation/CreateStack.hs
+++ b/gen/Network/AWS/CloudFormation/CreateStack.hs
@@ -126,10 +126,10 @@
 -- explicitly acknowledge their capabilities by specifying this parameter.
 --
 -- Currently, the only valid value is 'CAPABILITY_IAM', which is required for the
--- following resources: <http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-stack.html  AWS::CloudFormation::Stack>, <http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-iam-accesskey.html  AWS::IAM::AccessKey>, <http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-iam-group.html AWS::IAM::Group>, <http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-iam-instanceprofile.html  AWS::IAM::InstanceProfile>, <http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-iam-policy.html  AWS::IAM::Policy>, <http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-iam-role.html AWS::IAM::Role>, <http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-iam-user.html  AWS::IAM::User>, and <http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-iam-addusertogroup.html  AWS::IAM::UserToGroupAddition>. If your
--- stack template contains these resources, we recommend that you review any
--- permissions associated with them. If you don't specify this parameter, this
--- action returns an 'InsufficientCapabilities' error.
+-- following resources: <http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-iam-accesskey.html  AWS::IAM::AccessKey>, <http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-iam-group.html  AWS::IAM::Group>, <http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-iam-instanceprofile.html AWS::IAM::InstanceProfile>, <http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-iam-policy.html  AWS::IAM::Policy>, <http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-iam-role.html  AWS::IAM::Role>, <http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-iam-user.html  AWS::IAM::User>
+-- , and <http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-iam-addusertogroup.html  AWS::IAM::UserToGroupAddition>. If your stack template contains these
+-- resources, we recommend that you review any permissions associated with them.
+-- If you don't specify this parameter, this action returns an 'InsufficientCapabilities' error.
 csCapabilities :: Lens' CreateStack [Capability]
 csCapabilities = lens _csCapabilities (\s a -> s { _csCapabilities = a }) . _List
 
@@ -160,11 +160,12 @@
 csParameters :: Lens' CreateStack [Parameter]
 csParameters = lens _csParameters (\s a -> s { _csParameters = a }) . _List
 
--- | The name associated with the stack. The name must be unique within your AWS
--- account.
+-- | The name that is associated with the stack. The name must be unique in the
+-- region in which you are creating the stack.
 --
--- Must contain only alphanumeric characters (case sensitive) and start with an
--- alpha character. Maximum length of the name is 255 characters.
+-- A stack name can contain only alphanumeric characters (case sensitive) and
+-- hyphens. It must start with an alphabetic character and cannot be longer than
+-- 255 characters.
 csStackName :: Lens' CreateStack Text
 csStackName = lens _csStackName (\s a -> s { _csStackName = a })
 
@@ -199,7 +200,7 @@
 csTemplateBody = lens _csTemplateBody (\s a -> s { _csTemplateBody = a })
 
 -- | Location of file containing the template body. The URL must point to a
--- template (max size: 307,200 bytes) located in an S3 bucket in the same region
+-- template (max size: 460,800 bytes) located in an S3 bucket in the same region
 -- as the stack. For more information, go to the <http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/template-anatomy.html Template Anatomy> in the AWS
 -- CloudFormation User Guide.
 --
diff --git a/gen/Network/AWS/CloudFormation/DeleteStack.hs b/gen/Network/AWS/CloudFormation/DeleteStack.hs
--- a/gen/Network/AWS/CloudFormation/DeleteStack.hs
+++ b/gen/Network/AWS/CloudFormation/DeleteStack.hs
@@ -63,7 +63,7 @@
     { _dsStackName = p1
     }
 
--- | The name or the unique identifier associated with the stack.
+-- | The name or the unique stack ID that is associated with the stack.
 dsStackName :: Lens' DeleteStack Text
 dsStackName = lens _dsStackName (\s a -> s { _dsStackName = a })
 
diff --git a/gen/Network/AWS/CloudFormation/DescribeStackEvents.hs b/gen/Network/AWS/CloudFormation/DescribeStackEvents.hs
--- a/gen/Network/AWS/CloudFormation/DescribeStackEvents.hs
+++ b/gen/Network/AWS/CloudFormation/DescribeStackEvents.hs
@@ -79,8 +79,8 @@
 dseNextToken :: Lens' DescribeStackEvents (Maybe Text)
 dseNextToken = lens _dseNextToken (\s a -> s { _dseNextToken = a })
 
--- | The name or the unique identifier associated with the stack, which are not
--- always interchangeable:
+-- | The name or the unique stack ID that is associated with the stack, which are
+-- not always interchangeable:
 --
 -- Running stacks: You can specify either the stack's name or its unique stack
 -- ID. Deleted stacks: You must specify the unique stack ID.  Default: There is
diff --git a/gen/Network/AWS/CloudFormation/DescribeStackResource.hs b/gen/Network/AWS/CloudFormation/DescribeStackResource.hs
--- a/gen/Network/AWS/CloudFormation/DescribeStackResource.hs
+++ b/gen/Network/AWS/CloudFormation/DescribeStackResource.hs
@@ -79,8 +79,8 @@
 dsr1LogicalResourceId =
     lens _dsr1LogicalResourceId (\s a -> s { _dsr1LogicalResourceId = a })
 
--- | The name or the unique identifier associated with the stack, which are not
--- always interchangeable:
+-- | The name or the unique stack ID that is associated with the stack, which are
+-- not always interchangeable:
 --
 -- Running stacks: You can specify either the stack's name or its unique stack
 -- ID. Deleted stacks: You must specify the unique stack ID.  Default: There is
diff --git a/gen/Network/AWS/CloudFormation/DescribeStackResources.hs b/gen/Network/AWS/CloudFormation/DescribeStackResources.hs
--- a/gen/Network/AWS/CloudFormation/DescribeStackResources.hs
+++ b/gen/Network/AWS/CloudFormation/DescribeStackResources.hs
@@ -107,8 +107,8 @@
 dsrPhysicalResourceId =
     lens _dsrPhysicalResourceId (\s a -> s { _dsrPhysicalResourceId = a })
 
--- | The name or the unique identifier associated with the stack, which are not
--- always interchangeable:
+-- | The name or the unique stack ID that is associated with the stack, which are
+-- not always interchangeable:
 --
 -- Running stacks: You can specify either the stack's name or its unique stack
 -- ID. Deleted stacks: You must specify the unique stack ID.  Default: There is
diff --git a/gen/Network/AWS/CloudFormation/DescribeStacks.hs b/gen/Network/AWS/CloudFormation/DescribeStacks.hs
--- a/gen/Network/AWS/CloudFormation/DescribeStacks.hs
+++ b/gen/Network/AWS/CloudFormation/DescribeStacks.hs
@@ -73,8 +73,8 @@
 ds1NextToken :: Lens' DescribeStacks (Maybe Text)
 ds1NextToken = lens _ds1NextToken (\s a -> s { _ds1NextToken = a })
 
--- | The name or the unique identifier associated with the stack, which are not
--- always interchangeable:
+-- | The name or the unique stack ID that is associated with the stack, which are
+-- not always interchangeable:
 --
 -- Running stacks: You can specify either the stack's name or its unique stack
 -- ID. Deleted stacks: You must specify the unique stack ID.  Default: There is
diff --git a/gen/Network/AWS/CloudFormation/GetStackPolicy.hs b/gen/Network/AWS/CloudFormation/GetStackPolicy.hs
--- a/gen/Network/AWS/CloudFormation/GetStackPolicy.hs
+++ b/gen/Network/AWS/CloudFormation/GetStackPolicy.hs
@@ -64,8 +64,8 @@
     { _gspStackName = p1
     }
 
--- | The name or stack ID that is associated with the stack whose policy you want
--- to get.
+-- | The name or unique stack ID that is associated with the stack whose policy
+-- you want to get.
 gspStackName :: Lens' GetStackPolicy Text
 gspStackName = lens _gspStackName (\s a -> s { _gspStackName = a })
 
diff --git a/gen/Network/AWS/CloudFormation/GetTemplate.hs b/gen/Network/AWS/CloudFormation/GetTemplate.hs
--- a/gen/Network/AWS/CloudFormation/GetTemplate.hs
+++ b/gen/Network/AWS/CloudFormation/GetTemplate.hs
@@ -69,8 +69,8 @@
     { _gtStackName = p1
     }
 
--- | The name or the unique identifier associated with the stack, which are not
--- always interchangeable:
+-- | The name or the unique stack ID that is associated with the stack, which are
+-- not always interchangeable:
 --
 -- Running stacks: You can specify either the stack's name or its unique stack
 -- ID. Deleted stacks: You must specify the unique stack ID.  Default: There is
diff --git a/gen/Network/AWS/CloudFormation/GetTemplateSummary.hs b/gen/Network/AWS/CloudFormation/GetTemplateSummary.hs
--- a/gen/Network/AWS/CloudFormation/GetTemplateSummary.hs
+++ b/gen/Network/AWS/CloudFormation/GetTemplateSummary.hs
@@ -53,6 +53,7 @@
     , gtsrCapabilities
     , gtsrCapabilitiesReason
     , gtsrDescription
+    , gtsrMetadata
     , gtsrParameters
     , gtsrVersion
     ) where
@@ -85,7 +86,7 @@
     , _gtsStackName    = Nothing
     }
 
--- | The name or the unique identifier associated with the stack, which are not
+-- | The name or the stack ID that is associated with the stack, which are not
 -- always interchangeable. For running stacks, you can specify either the
 -- stack's name or its unique stack ID. For deleted stack, you must specify the
 -- unique stack ID.
@@ -104,7 +105,7 @@
 gtsTemplateBody = lens _gtsTemplateBody (\s a -> s { _gtsTemplateBody = a })
 
 -- | Location of file containing the template body. The URL must point to a
--- template (max size: 307,200 bytes) located in an Amazon S3 bucket. For more
+-- template (max size: 460,800 bytes) located in an Amazon S3 bucket. For more
 -- information about templates, see <http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/template-anatomy.html Template Anatomy> in the AWS CloudFormation
 -- User Guide.
 --
@@ -117,6 +118,7 @@
     { _gtsrCapabilities       :: List "member" Capability
     , _gtsrCapabilitiesReason :: Maybe Text
     , _gtsrDescription        :: Maybe Text
+    , _gtsrMetadata           :: Maybe Text
     , _gtsrParameters         :: List "member" ParameterDeclaration
     , _gtsrVersion            :: Maybe Text
     } deriving (Eq, Read, Show)
@@ -131,6 +133,8 @@
 --
 -- * 'gtsrDescription' @::@ 'Maybe' 'Text'
 --
+-- * 'gtsrMetadata' @::@ 'Maybe' 'Text'
+--
 -- * 'gtsrParameters' @::@ ['ParameterDeclaration']
 --
 -- * 'gtsrVersion' @::@ 'Maybe' 'Text'
@@ -142,6 +146,7 @@
     , _gtsrCapabilities       = mempty
     , _gtsrCapabilitiesReason = Nothing
     , _gtsrVersion            = Nothing
+    , _gtsrMetadata           = Nothing
     }
 
 -- | The capabilities found within the template. Currently, AWS CloudFormation
@@ -152,7 +157,8 @@
 gtsrCapabilities :: Lens' GetTemplateSummaryResponse [Capability]
 gtsrCapabilities = lens _gtsrCapabilities (\s a -> s { _gtsrCapabilities = a }) . _List
 
--- | The capabilities reason found within the template.
+-- | The list of resources that generated the values in the 'Capabilities' response
+-- element.
 gtsrCapabilitiesReason :: Lens' GetTemplateSummaryResponse (Maybe Text)
 gtsrCapabilitiesReason =
     lens _gtsrCapabilitiesReason (\s a -> s { _gtsrCapabilitiesReason = a })
@@ -161,6 +167,10 @@
 gtsrDescription :: Lens' GetTemplateSummaryResponse (Maybe Text)
 gtsrDescription = lens _gtsrDescription (\s a -> s { _gtsrDescription = a })
 
+-- | The value that is defined for the 'Metadata' property of the template.
+gtsrMetadata :: Lens' GetTemplateSummaryResponse (Maybe Text)
+gtsrMetadata = lens _gtsrMetadata (\s a -> s { _gtsrMetadata = a })
+
 -- | A list of parameter declarations that describe various properties for each
 -- parameter.
 gtsrParameters :: Lens' GetTemplateSummaryResponse [ParameterDeclaration]
@@ -195,5 +205,6 @@
         <$> x .@? "Capabilities" .!@ mempty
         <*> x .@? "CapabilitiesReason"
         <*> x .@? "Description"
+        <*> x .@? "Metadata"
         <*> x .@? "Parameters" .!@ mempty
         <*> x .@? "Version"
diff --git a/gen/Network/AWS/CloudFormation/ListStackResources.hs b/gen/Network/AWS/CloudFormation/ListStackResources.hs
--- a/gen/Network/AWS/CloudFormation/ListStackResources.hs
+++ b/gen/Network/AWS/CloudFormation/ListStackResources.hs
@@ -79,8 +79,8 @@
 lsrNextToken :: Lens' ListStackResources (Maybe Text)
 lsrNextToken = lens _lsrNextToken (\s a -> s { _lsrNextToken = a })
 
--- | The name or the unique identifier associated with the stack, which are not
--- always interchangeable:
+-- | The name or the unique stack ID that is associated with the stack, which are
+-- not always interchangeable:
 --
 -- Running stacks: You can specify either the stack's name or its unique stack
 -- ID. Deleted stacks: You must specify the unique stack ID.  Default: There is
diff --git a/gen/Network/AWS/CloudFormation/SetStackPolicy.hs b/gen/Network/AWS/CloudFormation/SetStackPolicy.hs
--- a/gen/Network/AWS/CloudFormation/SetStackPolicy.hs
+++ b/gen/Network/AWS/CloudFormation/SetStackPolicy.hs
@@ -71,7 +71,7 @@
     , _sspStackPolicyURL  = Nothing
     }
 
--- | The name or stack ID that you want to associate a policy with.
+-- | The name or unique stack ID that you want to associate a policy with.
 sspStackName :: Lens' SetStackPolicy Text
 sspStackName = lens _sspStackName (\s a -> s { _sspStackName = a })
 
diff --git a/gen/Network/AWS/CloudFormation/SignalResource.hs b/gen/Network/AWS/CloudFormation/SignalResource.hs
--- a/gen/Network/AWS/CloudFormation/SignalResource.hs
+++ b/gen/Network/AWS/CloudFormation/SignalResource.hs
@@ -90,7 +90,8 @@
 srLogicalResourceId =
     lens _srLogicalResourceId (\s a -> s { _srLogicalResourceId = a })
 
--- | The stack name or ID that includes the resource that you want to signal.
+-- | The stack name or unique stack ID that includes the resource that you want to
+-- signal.
 srStackName :: Lens' SignalResource Text
 srStackName = lens _srStackName (\s a -> s { _srStackName = a })
 
diff --git a/gen/Network/AWS/CloudFormation/Types.hs b/gen/Network/AWS/CloudFormation/Types.hs
--- a/gen/Network/AWS/CloudFormation/Types.hs
+++ b/gen/Network/AWS/CloudFormation/Types.hs
@@ -98,6 +98,7 @@
     , pdDefaultValue
     , pdDescription
     , pdNoEcho
+    , pdParameterConstraints
     , pdParameterKey
     , pdParameterType
 
@@ -121,6 +122,11 @@
     , oOutputKey
     , oOutputValue
 
+    -- * ParameterConstraints
+    , ParameterConstraints
+    , parameterConstraints
+    , pcAllowedValues
+
     -- * StackResourceSummary
     , StackResourceSummary
     , stackResourceSummary
@@ -206,7 +212,7 @@
               -> RESTError
               -> Bool
         check (statusCode -> s) (awsErrorCode -> e)
-            | s == 400 && "Throttling" == e = True -- Throttling
+            | s == 400 && (Just "Throttling") == e = True -- Throttling
             | s == 500  = True -- General Server Error
             | s == 509  = True -- Limit Exceeded
             | s == 503  = True -- Service Unavailable
@@ -801,12 +807,13 @@
         ]
 
 data ParameterDeclaration = ParameterDeclaration
-    { _pdDefaultValue  :: Maybe Text
-    , _pdDescription   :: Maybe Text
-    , _pdNoEcho        :: Maybe Bool
-    , _pdParameterKey  :: Maybe Text
-    , _pdParameterType :: Maybe Text
-    } deriving (Eq, Ord, Read, Show)
+    { _pdDefaultValue         :: Maybe Text
+    , _pdDescription          :: Maybe Text
+    , _pdNoEcho               :: Maybe Bool
+    , _pdParameterConstraints :: Maybe ParameterConstraints
+    , _pdParameterKey         :: Maybe Text
+    , _pdParameterType        :: Maybe Text
+    } deriving (Eq, Read, Show)
 
 -- | 'ParameterDeclaration' constructor.
 --
@@ -818,17 +825,20 @@
 --
 -- * 'pdNoEcho' @::@ 'Maybe' 'Bool'
 --
+-- * 'pdParameterConstraints' @::@ 'Maybe' 'ParameterConstraints'
+--
 -- * 'pdParameterKey' @::@ 'Maybe' 'Text'
 --
 -- * 'pdParameterType' @::@ 'Maybe' 'Text'
 --
 parameterDeclaration :: ParameterDeclaration
 parameterDeclaration = ParameterDeclaration
-    { _pdParameterKey  = Nothing
-    , _pdDefaultValue  = Nothing
-    , _pdParameterType = Nothing
-    , _pdNoEcho        = Nothing
-    , _pdDescription   = Nothing
+    { _pdParameterKey         = Nothing
+    , _pdDefaultValue         = Nothing
+    , _pdParameterType        = Nothing
+    , _pdNoEcho               = Nothing
+    , _pdDescription          = Nothing
+    , _pdParameterConstraints = Nothing
     }
 
 -- | The default value of the parameter.
@@ -844,6 +854,11 @@
 pdNoEcho :: Lens' ParameterDeclaration (Maybe Bool)
 pdNoEcho = lens _pdNoEcho (\s a -> s { _pdNoEcho = a })
 
+-- | The criteria that AWS CloudFormation uses to validate parameter values.
+pdParameterConstraints :: Lens' ParameterDeclaration (Maybe ParameterConstraints)
+pdParameterConstraints =
+    lens _pdParameterConstraints (\s a -> s { _pdParameterConstraints = a })
+
 -- | The name that is associated with the parameter.
 pdParameterKey :: Lens' ParameterDeclaration (Maybe Text)
 pdParameterKey = lens _pdParameterKey (\s a -> s { _pdParameterKey = a })
@@ -857,16 +872,18 @@
         <$> x .@? "DefaultValue"
         <*> x .@? "Description"
         <*> x .@? "NoEcho"
+        <*> x .@? "ParameterConstraints"
         <*> x .@? "ParameterKey"
         <*> x .@? "ParameterType"
 
 instance ToQuery ParameterDeclaration where
     toQuery ParameterDeclaration{..} = mconcat
-        [ "DefaultValue"  =? _pdDefaultValue
-        , "Description"   =? _pdDescription
-        , "NoEcho"        =? _pdNoEcho
-        , "ParameterKey"  =? _pdParameterKey
-        , "ParameterType" =? _pdParameterType
+        [ "DefaultValue"         =? _pdDefaultValue
+        , "Description"          =? _pdDescription
+        , "NoEcho"               =? _pdNoEcho
+        , "ParameterConstraints" =? _pdParameterConstraints
+        , "ParameterKey"         =? _pdParameterKey
+        , "ParameterType"        =? _pdParameterType
         ]
 
 data StackResource = StackResource
@@ -1035,6 +1052,40 @@
         , "OutputValue" =? _oOutputValue
         ]
 
+newtype ParameterConstraints = ParameterConstraints
+    { _pcAllowedValues :: List "member" Text
+    } deriving (Eq, Ord, Read, Show, Monoid, Semigroup)
+
+instance GHC.Exts.IsList ParameterConstraints where
+    type Item ParameterConstraints = Text
+
+    fromList = ParameterConstraints . GHC.Exts.fromList
+    toList   = GHC.Exts.toList . _pcAllowedValues
+
+-- | 'ParameterConstraints' constructor.
+--
+-- The fields accessible through corresponding lenses are:
+--
+-- * 'pcAllowedValues' @::@ ['Text']
+--
+parameterConstraints :: ParameterConstraints
+parameterConstraints = ParameterConstraints
+    { _pcAllowedValues = mempty
+    }
+
+-- | A list of values that are permitted for a parameter.
+pcAllowedValues :: Lens' ParameterConstraints [Text]
+pcAllowedValues = lens _pcAllowedValues (\s a -> s { _pcAllowedValues = a }) . _List
+
+instance FromXML ParameterConstraints where
+    parseXML x = ParameterConstraints
+        <$> x .@? "AllowedValues" .!@ mempty
+
+instance ToQuery ParameterConstraints where
+    toQuery ParameterConstraints{..} = mconcat
+        [ "AllowedValues" =? _pcAllowedValues
+        ]
+
 data StackResourceSummary = StackResourceSummary
     { _srsLastUpdatedTimestamp :: ISO8601
     , _srsLogicalResourceId    :: Text
@@ -1394,7 +1445,9 @@
     , _pUsePreviousValue = Nothing
     }
 
--- | The key associated with the parameter.
+-- | The key associated with the parameter. If you don't specify a key and value
+-- for a particular parameter, AWS CloudFormation uses the default value that is
+-- specified in your template.
 pParameterKey :: Lens' Parameter (Maybe Text)
 pParameterKey = lens _pParameterKey (\s a -> s { _pParameterKey = a })
 
@@ -1402,8 +1455,9 @@
 pParameterValue :: Lens' Parameter (Maybe Text)
 pParameterValue = lens _pParameterValue (\s a -> s { _pParameterValue = a })
 
--- | During a stack update, use the existing parameter value that is being used
--- for the stack.
+-- | During a stack update, use the existing parameter value that the stack is
+-- using for a given parameter key. If you specify 'true', do not specify a
+-- parameter value.
 pUsePreviousValue :: Lens' Parameter (Maybe Bool)
 pUsePreviousValue =
     lens _pUsePreviousValue (\s a -> s { _pUsePreviousValue = a })
diff --git a/gen/Network/AWS/CloudFormation/UpdateStack.hs b/gen/Network/AWS/CloudFormation/UpdateStack.hs
--- a/gen/Network/AWS/CloudFormation/UpdateStack.hs
+++ b/gen/Network/AWS/CloudFormation/UpdateStack.hs
@@ -128,10 +128,11 @@
 -- that can affect permissions in your AWS account. For those stacks, you must
 -- explicitly acknowledge their capabilities by specifying this parameter.
 -- Currently, the only valid value is 'CAPABILITY_IAM', which is required for the
--- following resources: <http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-stack.html  AWS::CloudFormation::Stack>, <http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-iam-accesskey.html  AWS::IAM::AccessKey>, <http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-iam-group.html AWS::IAM::Group>, <http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-iam-instanceprofile.html  AWS::IAM::InstanceProfile>, <http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-iam-policy.html  AWS::IAM::Policy>, <http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-iam-role.html AWS::IAM::Role>, <http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-iam-user.html  AWS::IAM::User>, and <http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-iam-addusertogroup.html  AWS::IAM::UserToGroupAddition>. If your
--- stack template contains these resources, we recommend that you review any
--- permissions associated with them. If you don't specify this parameter, this
--- action returns an InsufficientCapabilities error.
+-- following resources: <http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-iam-accesskey.html  AWS::IAM::AccessKey>, <http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-iam-group.html  AWS::IAM::Group>, <http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-iam-instanceprofile.html AWS::IAM::InstanceProfile>, <http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-iam-policy.html  AWS::IAM::Policy>, <http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-iam-role.html  AWS::IAM::Role>, <http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-iam-user.html  AWS::IAM::User>
+-- , and <http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-iam-addusertogroup.html  AWS::IAM::UserToGroupAddition>. If your stack template contains these
+-- resources, we recommend that you review any permissions associated with them.
+-- If you don't specify this parameter, this action returns an
+-- InsufficientCapabilities error.
 usCapabilities :: Lens' UpdateStack [Capability]
 usCapabilities = lens _usCapabilities (\s a -> s { _usCapabilities = a }) . _List
 
@@ -142,13 +143,11 @@
         . _List
 
 -- | A list of 'Parameter' structures that specify input parameters for the stack.
+-- For more information, see the <http://docs.aws.amazon.com/AWSCloudFormation/latest/APIReference/API_Parameter.html Parameter> data type.
 usParameters :: Lens' UpdateStack [Parameter]
 usParameters = lens _usParameters (\s a -> s { _usParameters = a }) . _List
 
--- | The name or stack ID of the stack to update.
---
--- Must contain only alphanumeric characters (case sensitive) and start with
--- an alpha character. Maximum length of the name is 255 characters.
+-- | The name or unique stack ID of the stack to update.
 usStackName :: Lens' UpdateStack Text
 usStackName = lens _usStackName (\s a -> s { _usStackName = a })
 
diff --git a/gen/Network/AWS/CloudFormation/ValidateTemplate.hs b/gen/Network/AWS/CloudFormation/ValidateTemplate.hs
--- a/gen/Network/AWS/CloudFormation/ValidateTemplate.hs
+++ b/gen/Network/AWS/CloudFormation/ValidateTemplate.hs
@@ -80,7 +80,7 @@
 vtTemplateBody = lens _vtTemplateBody (\s a -> s { _vtTemplateBody = a })
 
 -- | Location of file containing the template body. The URL must point to a
--- template (max size: 307,200 bytes) located in an S3 bucket in the same region
+-- template (max size: 460,800 bytes) located in an S3 bucket in the same region
 -- as the stack. For more information, go to <http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/template-anatomy.html Template Anatomy> in the AWS
 -- CloudFormation User Guide.
 --
@@ -124,7 +124,8 @@
 vtrCapabilities :: Lens' ValidateTemplateResponse [Capability]
 vtrCapabilities = lens _vtrCapabilities (\s a -> s { _vtrCapabilities = a }) . _List
 
--- | The capabilities reason found within the template.
+-- | The list of resources that generated the values in the 'Capabilities' response
+-- element.
 vtrCapabilitiesReason :: Lens' ValidateTemplateResponse (Maybe Text)
 vtrCapabilitiesReason =
     lens _vtrCapabilitiesReason (\s a -> s { _vtrCapabilitiesReason = a })
