diff --git a/core/src/main/java/org/jruby/RubyString.java b/core/src/main/java/org/jruby/RubyString.java
index 6eef74dcb15..fbd2fdce4c9 100644
--- a/core/src/main/java/org/jruby/RubyString.java
+++ b/core/src/main/java/org/jruby/RubyString.java
@@ -1374,6 +1374,13 @@ public final RubyString cat(byte[] str, int beg, int len) {
         return this;
     }
 
+    // Needs to remain in place until StringIO has migrated to the new methods
+    // See https://github.com/ruby/stringio/issues/83
+    @Deprecated
+    public final RubyString cat19(RubyString str2) {
+        return catWithCodeRange(str2);
+    }
+
     // // rb_str_buf_append against VALUE
     public final RubyString catWithCodeRange(RubyString str2) {
         ByteList other = str2.getByteList();
@@ -1389,6 +1396,13 @@ public final RubyString cat(ByteList other, int codeRange) {
         return this;
     }
 
+    // Needs to remain in place until StringIO has migrated to the new methods
+    // See https://github.com/ruby/stringio/issues/83
+    @Deprecated
+    public final int cat19(ByteList other, int codeRange) {
+        return catWithCodeRange(other, codeRange);
+    }
+
     // rb_str_buf_append against ptr
     public final int catWithCodeRange(ByteList other, int codeRange) {
         return EncodingUtils.encCrStrBufCat(metaClass.runtime, this, other, other.getEncoding(), codeRange);