diff --git a/.changes/1669a4b4-4b10-4ca6-b11a-43bf5413de19.json b/.changes/1669a4b4-4b10-4ca6-b11a-43bf5413de19.json
new file mode 100644
index 0000000000..6c08e1378d
--- /dev/null
+++ b/.changes/1669a4b4-4b10-4ca6-b11a-43bf5413de19.json
@@ -0,0 +1,5 @@
+{
+    "id": "1669a4b4-4b10-4ca6-b11a-43bf5413de19",
+    "type": "misc",
+    "description": "Upgrade to Smithy 1.49.0"
+}
\ No newline at end of file
diff --git a/codegen/smithy-aws-kotlin-codegen/src/main/kotlin/software/amazon/smithy/kotlin/codegen/aws/protocols/Ec2Query.kt b/codegen/smithy-aws-kotlin-codegen/src/main/kotlin/software/amazon/smithy/kotlin/codegen/aws/protocols/Ec2Query.kt
index e318804322..10be8bfc6e 100644
--- a/codegen/smithy-aws-kotlin-codegen/src/main/kotlin/software/amazon/smithy/kotlin/codegen/aws/protocols/Ec2Query.kt
+++ b/codegen/smithy-aws-kotlin-codegen/src/main/kotlin/software/amazon/smithy/kotlin/codegen/aws/protocols/Ec2Query.kt
@@ -10,16 +10,15 @@ import software.amazon.smithy.codegen.core.Symbol
 import software.amazon.smithy.kotlin.codegen.aws.protocols.core.AbstractQueryFormUrlSerializerGenerator
 import software.amazon.smithy.kotlin.codegen.aws.protocols.core.QueryHttpBindingProtocolGenerator
 import software.amazon.smithy.kotlin.codegen.aws.protocols.formurl.QuerySerdeFormUrlDescriptorGenerator
-import software.amazon.smithy.kotlin.codegen.core.KotlinWriter
-import software.amazon.smithy.kotlin.codegen.core.RenderingContext
-import software.amazon.smithy.kotlin.codegen.core.RuntimeTypes
-import software.amazon.smithy.kotlin.codegen.core.withBlock
+import software.amazon.smithy.kotlin.codegen.core.*
 import software.amazon.smithy.kotlin.codegen.model.buildSymbol
 import software.amazon.smithy.kotlin.codegen.model.getTrait
+import software.amazon.smithy.kotlin.codegen.model.isNullable
 import software.amazon.smithy.kotlin.codegen.rendering.protocol.ProtocolGenerator
 import software.amazon.smithy.kotlin.codegen.rendering.protocol.toRenderingContext
 import software.amazon.smithy.kotlin.codegen.rendering.serde.*
 import software.amazon.smithy.model.shapes.*
+import software.amazon.smithy.model.traits.TimestampFormatTrait
 import software.amazon.smithy.model.traits.XmlNameTrait
 
 /**
@@ -76,6 +75,20 @@ private class Ec2QuerySerializerGenerator(
     private val protocolGenerator: Ec2Query,
 ) : AbstractQueryFormUrlSerializerGenerator(protocolGenerator, protocolGenerator.defaultTimestampFormat) {
 
+    override fun renderSerializerBody(
+        ctx: ProtocolGenerator.GenerationContext,
+        shape: Shape,
+        members: List<MemberShape>,
+        writer: KotlinWriter,
+    ) {
+        // render the serde descriptors
+        descriptorGenerator(ctx, shape, members, writer).render()
+        when (shape) {
+            is UnionShape -> SerializeUnionGenerator(ctx, shape, members, writer, protocolGenerator.defaultTimestampFormat).render()
+            else -> Ec2QuerySerializeStructGenerator(ctx, members, writer, protocolGenerator.defaultTimestampFormat).render()
+        }
+    }
+
     override fun descriptorGenerator(
         ctx: ProtocolGenerator.GenerationContext,
         shape: Shape,
@@ -155,3 +168,34 @@ private class Ec2QueryParserGenerator(
         }
     }
 }
+
+/**
+ * An EC2 Query implementation of [SerializeStructGenerator] which ensures that empty lists are not serialized.
+ */
+private class Ec2QuerySerializeStructGenerator(
+    ctx: ProtocolGenerator.GenerationContext,
+    members: List<MemberShape>,
+    writer: KotlinWriter,
+    defaultTimestampFormat: TimestampFormatTrait.Format,
+) : SerializeStructGenerator(ctx, members, writer, defaultTimestampFormat) {
+    override fun renderListMemberSerializer(memberShape: MemberShape, targetShape: CollectionShape) {
+        val memberName = ctx.symbolProvider.toMemberName(memberShape)
+        val descriptorName = memberShape.descriptorName()
+        val nestingLevel = 0
+        val memberSymbol = ctx.symbolProvider.toSymbol(memberShape)
+
+        if (memberSymbol.isNullable) {
+            writer.withBlock("if (!input.$memberName.isNullOrEmpty()) {", "}") {
+                writer.withBlock("listField($descriptorName) {", "}") {
+                    delegateListSerialization(memberShape, targetShape, nestingLevel, memberName)
+                }
+            }
+        } else {
+            writer.withBlock("if (input.$memberName.isNotEmpty()) {", "}") {
+                writer.withBlock("listField($descriptorName) {", "}") {
+                    delegateListSerialization(memberShape, targetShape, nestingLevel, memberName)
+                }
+            }
+        }
+    }
+}
diff --git a/codegen/smithy-aws-kotlin-codegen/src/main/kotlin/software/amazon/smithy/kotlin/codegen/aws/protocols/core/QueryHttpBindingProtocolGenerator.kt b/codegen/smithy-aws-kotlin-codegen/src/main/kotlin/software/amazon/smithy/kotlin/codegen/aws/protocols/core/QueryHttpBindingProtocolGenerator.kt
index c79bc20bc1..21fac173ef 100644
--- a/codegen/smithy-aws-kotlin-codegen/src/main/kotlin/software/amazon/smithy/kotlin/codegen/aws/protocols/core/QueryHttpBindingProtocolGenerator.kt
+++ b/codegen/smithy-aws-kotlin-codegen/src/main/kotlin/software/amazon/smithy/kotlin/codegen/aws/protocols/core/QueryHttpBindingProtocolGenerator.kt
@@ -151,7 +151,7 @@ abstract class AbstractQueryFormUrlSerializerGenerator(
         }
     }
 
-    private fun renderSerializerBody(
+    open fun renderSerializerBody(
         ctx: ProtocolGenerator.GenerationContext,
         shape: Shape,
         members: List<MemberShape>,
diff --git a/codegen/smithy-kotlin-codegen/src/main/kotlin/software/amazon/smithy/kotlin/codegen/model/RulesEngineExt.kt b/codegen/smithy-kotlin-codegen/src/main/kotlin/software/amazon/smithy/kotlin/codegen/model/RulesEngineExt.kt
index 67057f1087..1428516fc9 100644
--- a/codegen/smithy-kotlin-codegen/src/main/kotlin/software/amazon/smithy/kotlin/codegen/model/RulesEngineExt.kt
+++ b/codegen/smithy-kotlin-codegen/src/main/kotlin/software/amazon/smithy/kotlin/codegen/model/RulesEngineExt.kt
@@ -32,8 +32,8 @@ fun ParameterType.toSymbol(): Symbol =
     when (this) {
         ParameterType.STRING -> KotlinTypes.String
         ParameterType.BOOLEAN -> KotlinTypes.Boolean
-    }
-        .asNullable()
+        ParameterType.STRING_ARRAY -> KotlinTypes.Collections.MutableList
+    }.asNullable()
 
 /**
  * Get the writable literal for a rules engine value.
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index a5a39af9e3..7db994687f 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -15,7 +15,7 @@ slf4j-v1x-version = "1.7.36"
 crt-kotlin-version = "0.8.5"
 
 # codegen
-smithy-version = "1.47.0"
+smithy-version = "1.49.0"
 smithy-gradle-version = "0.9.0"
 
 # testing