diff --git a/StructFields.pm b/StructFields.pm
index 4d0e1fddc..a09621542 100644
--- a/StructFields.pm
+++ b/StructFields.pm
@@ -98,6 +98,7 @@ my %custom_primitive_handlers = (
     'stl-fstream' => sub { header_ref("fstream"); return "std::fstream"; },
     'stl-mutex' => sub { header_ref("mutex"); return "std::mutex"; },
     'stl-condition-variable' => sub { header_ref("condition_variable"); return "std::condition_variable"; },
+    'stl-future' => sub { header_ref("future"); return "std::future<void>"; },
 );
 
 my %custom_primitive_inits = (
diff --git a/data-definition.xsd b/data-definition.xsd
index e5566d710..7648e69d5 100644
--- a/data-definition.xsd
+++ b/data-definition.xsd
@@ -222,6 +222,7 @@
             <xs:element name="stl-fstream" type="OpaqueField" />
             <xs:element name="stl-mutex" type="OpaqueField" />
             <xs:element name="stl-condition-variable" type="OpaqueField" />
+            <xs:element name="stl-future" type="OpaqueField" />
             <xs:element name="df-linked-list" type="DfLinkedListField" />
             <xs:element name="df-array" type="DfArrayField" />
             <xs:element name="df-flagarray" type="DfFlagArrayField" />
diff --git a/df.viewscreen.xml b/df.viewscreen.xml
index b913c14ca..38a78c832 100644
--- a/df.viewscreen.xml
+++ b/df.viewscreen.xml
@@ -684,6 +684,7 @@
     <class-type type-name='viewscreen_initial_prepst' inherits-from='viewscreen'>
         <int32_t name='render_count'/>
         <int32_t name='logic_step'/>
+        <stl-future name='unk_90'/>
     </class-type>
 
     <class-type type-name='world_gen_param_basest'>
@@ -845,10 +846,8 @@
         <stl-vector pointer-type='legend_pagest' name='page'/>
         <int32_t name='active_page_index'/>
         <int32_t name='page_scroll'/>
-        <pointer name='unk_338'/>
-        <int32_t name='unk_340'/>
-        <int32_t name='unk_344'/>
-        <int32_t name='unk_348'/>
+        <stl-future name='unk_338'/>
+        <int8_t name='unk_348'/>
     </class-type>
 
     <struct-type type-name='loadgame_save_info'>
diff --git a/lower-1.xslt b/lower-1.xslt
index 1306f2fbc..4733ad413 100644
--- a/lower-1.xslt
+++ b/lower-1.xslt
@@ -217,9 +217,10 @@ Error: field <xsl:value-of select='$enum-key'/> corresponds to an enum value of
         <prim-type ld:meta='primitive' ld:subtype='stl-fstream'/>
         <prim-type ld:meta='primitive' ld:subtype='stl-mutex'/>
         <prim-type ld:meta='primitive' ld:subtype='stl-condition-variable'/>
+        <prim-type ld:meta='primitive' ld:subtype='stl-future'/>
     </ld:primitive-types>
 
-    <xsl:template match='int8_t|uint8_t|int16_t|uint16_t|int32_t|uint32_t|int64_t|uint64_t|size_t|ssize_t|long|ulong|bool|flag-bit|s-float|d-float|padding|static-string|ptr-string|stl-string|stl-fstream|stl-mutex|stl-condition-variable'>
+    <xsl:template match='int8_t|uint8_t|int16_t|uint16_t|int32_t|uint32_t|int64_t|uint64_t|size_t|ssize_t|long|ulong|bool|flag-bit|s-float|d-float|padding|static-string|ptr-string|stl-string|stl-fstream|stl-mutex|stl-condition-variable|stl-future'>
         <xsl:param name='level' select='-1'/>
         <ld:field>
             <xsl:apply-templates select='@*'/>