diff --git a/examples/qtest/attach-file/output.pdf b/examples/qtest/attach-file/output.pdf
index d41cef4f..ab09055c 100644
Binary files a/examples/qtest/attach-file/output.pdf and b/examples/qtest/attach-file/output.pdf differ
diff --git a/libqpdf/QPDFEFStreamObjectHelper.cc b/libqpdf/QPDFEFStreamObjectHelper.cc
index 47df9657..71e13cb2 100644
--- a/libqpdf/QPDFEFStreamObjectHelper.cc
+++ b/libqpdf/QPDFEFStreamObjectHelper.cc
@@ -76,7 +76,7 @@ QPDFEFStreamObjectHelper::getSize()
 std::string
 QPDFEFStreamObjectHelper::getSubtype()
 {
-    auto val = getParam("/Subtype");
+    auto val = this->oh.getDict().getKey("/Subtype");
     if (val.isName())
     {
         auto n = val.getName();
@@ -141,7 +141,8 @@ QPDFEFStreamObjectHelper::setModDate(std::string const& date)
 QPDFEFStreamObjectHelper&
 QPDFEFStreamObjectHelper::setSubtype(std::string const& subtype)
 {
-    setParam("/Subtype", QPDFObjectHandle::newName("/" + subtype));
+    this->oh.getDict().replaceKey(
+        "/Subtype", QPDFObjectHandle::newName("/" + subtype));
     return *this;
 }
 
diff --git a/qpdf/qtest/qpdf/add-attachments-1.pdf b/qpdf/qtest/qpdf/add-attachments-1.pdf
index 9605188f..172f617d 100644
--- a/qpdf/qtest/qpdf/add-attachments-1.pdf
+++ b/qpdf/qtest/qpdf/add-attachments-1.pdf
@@ -101,8 +101,8 @@ endobj
     /CreationDate (D:20210210091359-05'00')
     /ModDate (D:20210210141359Z)
     /Size 12
-    /Subtype /text#2fplain
   >>
+  /Subtype /text#2fplain
   /Type /EmbeddedFile
   /Length 9 0 R
 >>
@@ -204,20 +204,20 @@ xref
 0000000587 00000 n 
 0000000709 00000 n 
 0000000904 00000 n 
-0000001199 00000 n 
-0000001218 00000 n 
-0000001488 00000 n 
-0000001508 00000 n 
-0000001778 00000 n 
-0000001821 00000 n 
-0000001922 00000 n 
-0000001942 00000 n 
-0000002061 00000 n 
+0000001197 00000 n 
+0000001216 00000 n 
+0000001486 00000 n 
+0000001506 00000 n 
+0000001776 00000 n 
+0000001819 00000 n 
+0000001920 00000 n 
+0000001940 00000 n 
+0000002059 00000 n 
 trailer <<
   /Root 1 0 R
   /Size 18
   /ID [<31415926535897932384626433832795><31415926535897932384626433832795>]
 >>
 startxref
-2097
+2095
 %%EOF
diff --git a/qpdf/qtest/qpdf/copy-attachments-2.pdf b/qpdf/qtest/qpdf/copy-attachments-2.pdf
index a2f29598..83a873c2 100644
--- a/qpdf/qtest/qpdf/copy-attachments-2.pdf
+++ b/qpdf/qtest/qpdf/copy-attachments-2.pdf
@@ -144,8 +144,8 @@ endobj
     /CreationDate (D:20210210091359-05'00')
     /ModDate (D:20210210141359Z)
     /Size 12
-    /Subtype /text#2fplain
   >>
+  /Subtype /text#2fplain
   /Type /EmbeddedFile
   /Length 12 0 R
 >>
@@ -208,8 +208,8 @@ endobj
     /CreationDate (D:20210210091359-05'00')
     /ModDate (D:20210210141359Z)
     /Size 12
-    /Subtype /text#2fplain
   >>
+  /Subtype /text#2fplain
   /Type /EmbeddedFile
   /Length 18 0 R
 >>
@@ -314,26 +314,26 @@ xref
 0000001039 00000 n 
 0000001161 00000 n 
 0000001357 00000 n 
-0000001654 00000 n 
-0000001674 00000 n 
-0000001944 00000 n 
-0000001964 00000 n 
-0000002234 00000 n 
-0000002254 00000 n 
-0000002551 00000 n 
-0000002571 00000 n 
-0000002841 00000 n 
-0000002861 00000 n 
-0000003131 00000 n 
-0000003174 00000 n 
-0000003275 00000 n 
-0000003295 00000 n 
-0000003414 00000 n 
+0000001652 00000 n 
+0000001672 00000 n 
+0000001942 00000 n 
+0000001962 00000 n 
+0000002232 00000 n 
+0000002252 00000 n 
+0000002547 00000 n 
+0000002567 00000 n 
+0000002837 00000 n 
+0000002857 00000 n 
+0000003127 00000 n 
+0000003170 00000 n 
+0000003271 00000 n 
+0000003291 00000 n 
+0000003410 00000 n 
 trailer <<
   /Root 1 0 R
   /Size 27
   /ID [<31415926535897932384626433832795><31415926535897932384626433832795>]
 >>
 startxref
-3450
+3446
 %%EOF
diff --git a/qpdf/qtest/qpdf/test76.pdf b/qpdf/qtest/qpdf/test76.pdf
index d81d03f7..02d2d5cb 100644
--- a/qpdf/qtest/qpdf/test76.pdf
+++ b/qpdf/qtest/qpdf/test76.pdf
@@ -108,8 +108,8 @@ endobj
     /CreationDate (D:20210207191121-05'00')
     /ModDate (D:20210208001122Z)
     /Size 9
-    /Subtype /text#2fplain
   >>
+  /Subtype /text#2fplain
   /Type /EmbeddedFile
   /Length 9 0 R
 >>
@@ -129,8 +129,8 @@ endobj
   /Params <<
     /CheckSum <2fce9c8228e360ba9b04a1bd1bf63d6b>
     /Size 11
-    /Subtype /text#2fplain
   >>
+  /Subtype /text#2fplain
   /Type /EmbeddedFile
   /Length 11 0 R
 >>
@@ -150,8 +150,8 @@ endobj
   /Params <<
     /CheckSum <2236c155b1d62b7f00285bba081d4336>
     /Size 11
-    /Subtype /text#2fplain
   >>
+  /Subtype /text#2fplain
   /Type /EmbeddedFile
   /Length 13 0 R
 >>
@@ -214,20 +214,20 @@ xref
 0000000707 00000 n 
 0000000876 00000 n 
 0000001098 00000 n 
-0000001389 00000 n 
-0000001435 00000 n 
-0000001654 00000 n 
-0000001702 00000 n 
-0000001921 00000 n 
-0000001991 00000 n 
-0000002092 00000 n 
-0000002139 00000 n 
-0000002285 00000 n 
+0000001387 00000 n 
+0000001433 00000 n 
+0000001650 00000 n 
+0000001698 00000 n 
+0000001915 00000 n 
+0000001985 00000 n 
+0000002086 00000 n 
+0000002133 00000 n 
+0000002279 00000 n 
 trailer <<
   /Root 1 0 R
   /Size 18
   /ID [<31415926535897932384626433832795><31415926535897932384626433832795>]
 >>
 startxref
-2321
+2315
 %%EOF
diff --git a/qpdf/qtest/qpdf/test77.pdf b/qpdf/qtest/qpdf/test77.pdf
index 4aa01abf..468db017 100644
--- a/qpdf/qtest/qpdf/test77.pdf
+++ b/qpdf/qtest/qpdf/test77.pdf
@@ -93,8 +93,8 @@ endobj
     /CreationDate (D:20210207191121-05'00')
     /ModDate (D:20210208001122Z)
     /Size 9
-    /Subtype /text#2fplain
   >>
+  /Subtype /text#2fplain
   /Type /EmbeddedFile
   /Length 8 0 R
 >>
@@ -114,8 +114,8 @@ endobj
   /Params <<
     /CheckSum <2236c155b1d62b7f00285bba081d4336>
     /Size 11
-    /Subtype /text#2fplain
   >>
+  /Subtype /text#2fplain
   /Type /EmbeddedFile
   /Length 10 0 R
 >>
@@ -177,18 +177,18 @@ xref
 0000000541 00000 n 
 0000000708 00000 n 
 0000000930 00000 n 
-0000001221 00000 n 
-0000001267 00000 n 
-0000001485 00000 n 
-0000001556 00000 n 
-0000001657 00000 n 
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+0000001481 00000 n 
+0000001552 00000 n 
+0000001653 00000 n 
+0000001701 00000 n 
+0000001848 00000 n 
 trailer <<
   /Root 1 0 R
   /Size 15
   /ID [<31415926535897932384626433832795><31415926535897932384626433832795>]
 >>
 startxref
-1888
+1884
 %%EOF