diff --git a/build.sbt b/build.sbt
index 237d6a5..42b3315 100644
--- a/build.sbt
+++ b/build.sbt
@@ -3,8 +3,8 @@ ThisBuild / scalaVersion := "3.3.8"
 
 val fs2DataVersion = "1.8.1"
 val http4sVersion = "0.23.36"
-val latisVersion  = "b66ec47"
-val latisHapiVersion = "1a507d1"
+val latisVersion  = "c1531e77"
+val latisHapiVersion = "1d65ba50"
 
 lazy val root = (project in file("."))
   .settings(
diff --git a/src/main/scala/latis/ops/ConvertHapiTypes.scala b/src/main/scala/latis/ops/ConvertHapiTypes.scala
index e0cf68d..a6bb99c 100644
--- a/src/main/scala/latis/ops/ConvertHapiTypes.scala
+++ b/src/main/scala/latis/ops/ConvertHapiTypes.scala
@@ -10,23 +10,38 @@ import latis.util.LatisException
 /**
  * Converts scalar values to be consistent with supported HAPI types.
  *
- * HAPI supports only double, int, and string types. This will convert
- * some types that can safely be converted. Datasets with other types
- * will be excluded from the Catalog by HapiService.filteredCatalog.
- * This operation needs to be consistent with that filter.
+ * HAPI supports only doubles, 32-bit integers, and string types.
+ * This will convert LaTiS types that can safely be converted. Longs
+ * are an exception. Although HAPI does not support 64-bit integers,
+ * they are common enough in data sources (even when an int is sufficient)
+ * that this attempts to convert long values to 32-bit integers. If the
+ * long value exceeds the range of an Int, a fill value will be used
+ * if defined for that variable. Otherwise, an exception will be thrown.
  *
- * This is only needed for the binary output.
+ * Datasets with other types will be excluded from the Catalog by
+ * HapiService.filteredCatalog. This operation needs to be consistent
+ * with that filter.
+ *
+ * This assumes flat datasets with no nesting.
+ *
+ * This is only needed for the binary output, so it is otherwise not
+ * applicable.
  */
 class ConvertHapiTypes extends MapOperation {
-  //TODO: assumes non-nested functions or tuples
 
   def mapFunction(model: DataType): Sample => Sample = {
     // Note, domain can only be time and it is handled elsewhere
-    case Sample(d, r) => Sample(d, RangeData(r.map(convertValue)))
+    case Sample(d, r) =>
+      val rdata = model.getScalars.tail.zip(r).map(convertValue)
+      Sample(d, RangeData(rdata))
   }
 
-  private def convertValue(data: Data): Data = data match {
+  private def convertValue(scalar: Scalar, data: Data): Data = data match {
     case v: ShortValue => IntValue(v.value.toInt)
+    case v: LongValue  =>
+      if (v.value > Int.MaxValue.toLong || v.value < Int.MinValue.toLong)
+        scalar.fillValue.getOrElse(throw LatisException("Integer overflow"))
+      else IntValue(v.value.toInt)
     case v: FloatValue => DoubleValue(v.value.toDouble)
     case _             => data //no-op, shouldn't get here due to catalog filter
   }
@@ -45,6 +60,10 @@ class ConvertHapiTypes extends MapOperation {
       Scalar.fromMetadata(
         scalar.metadata + ("type" -> "int")
       ).fold(throw _, identity) //should not fail
+    case LongValueType =>
+      Scalar.fromMetadata(
+        scalar.metadata + ("type" -> "int")
+      ).fold(throw _, identity) //should not fail
     case _ => scalar //no-op, shouldn't get here due to catalog filter
   }
 }
diff --git a/src/main/scala/latis/service/hapi/HapiService.scala b/src/main/scala/latis/service/hapi/HapiService.scala
index 8a93310..bcbd4cd 100644
--- a/src/main/scala/latis/service/hapi/HapiService.scala
+++ b/src/main/scala/latis/service/hapi/HapiService.scala
@@ -42,16 +42,18 @@ class HapiService(catalog: Catalog) extends ServiceInterface(catalog, OperationR
   // This checks that:
   // - The Dataset metadata has temporalCoverage
   // - The single domain variable is of type Time
-  // - Each scalar in the range has a supported type
+  // - Each scalar in the range has a supported or convertible type
   // - If the type of a scalar is string, its size is defined
+  // - If the type is "long" a fillValue must be defined
   private val filteredCatalog: Catalog = {
     val covP:  Metadata => Boolean = _.getProperty("temporalCoverage").isDefined
     val typeP: Metadata => Boolean = md => md.getProperty("type").exists {
       case "string" => md.getProperty("size").isDefined
       case "double" => true
       case "int"    => true
-      case "float"  => true //may be converted to double by ConvertHapiTypes
-      case "short"  => true //may be converted to int by ConvertHapiTypes
+      case "long"   => md.getProperty("fillValue").isDefined
+      case "float"  => true //converted to double by ConvertHapiTypes
+      case "short"  => true //converted to int by ConvertHapiTypes
       case _        => false
     }