diff --git a/uppsrc/Core/src.tpp/Zlib$en-us.tpp b/uppsrc/Core/src.tpp/Zlib$en-us.tpp
index 0d583109e..6e7745083 100644
--- a/uppsrc/Core/src.tpp/Zlib$en-us.tpp
+++ b/uppsrc/Core/src.tpp/Zlib$en-us.tpp
@@ -128,10 +128,11 @@ in single zlib call.&]
 [s0; &]
 [ {{10000@(113.42.0) [s0;%% [*@7;4 Compression / decompression functions]]}}&]
 [s3; &]
-[s5;:ZCompress`(Stream`&`,Stream`&`,int64`,Gate2`<int64`,int64`>`): [_^int64^ int64]_[* Z
-Compress]([_^Stream^ Stream][@(0.0.255) `&]_[*@3 out], [_^Stream^ Stream][@(0.0.255) `&]_[*@3 i
-n], [_^int64^ int64]_[*@3 size], [_^Gate2^ Gate2]<[_^int64^ int64], [_^int64^ int64]>_[*@3 pr
-ogress]_`=_[@(0.0.255) false])&]
+[s5;:ZCompress`(Stream`&`,Stream`&`,int64`,Gate2`<int64`,int64`>`,bool`): [_^int64^ int
+64]_[* ZCompress]([_^Stream^ Stream][@(0.0.255) `&]_[*@3 out], [_^Stream^ Stream][@(0.0.255) `&
+]_[*@3 in], [_^int64^ int64]_[*@3 size], [_^Gate2^ Gate2]<[_^int64^ int64], 
+[_^int64^ int64]>_[*@3 progress]_`=_[@(0.0.255) false], [@(0.0.255) bool]_[*@3 hdr]_`=_[@(0.0.255) t
+rue])&]
 [s5;:ZCompress`(Stream`&`,Stream`&`,Gate2`<int64`,int64`>`): [_^int64^ int64]_[* ZCompres
 s]([_^Stream^ Stream][@(0.0.255) `&]_[*@3 out], [_^Stream^ Stream][@(0.0.255) `&]_[*@3 in], 
 [_^Gate2^ Gate2]<[_^int64^ int64], [_^int64^ int64]>_[*@3 progress]_`=_[@(0.0.255) false])&]
@@ -146,9 +147,16 @@ memory [%-*@3 data][%- , ][%-*@3 len] or input string [%-*@3 s] to output
 stream [%-*@3 out] (in this case returns a number of bytes written 
 or negative integer to signal error) or into String return value 
 (returns IsVoid String on error). [%-*@3 progress] can be used 
-to track progress of operation, returning true cancels operation.&]
+to track progress of operation, returning true cancels operation. 
+Parameter [%-*@3 hdr] can be used to switch`-off zlib header (see 
+zlib documentation for details).&]
 [s3;%% &]
-[s4;%% &]
+[s4; &]
+[s5;:ZDecompress`(Stream`&`,Stream`&`,int64`,Gate2`<int64`,int64`>`,bool`): [_^int64^ i
+nt64]_[* ZDecompress]([_^Stream^ Stream][@(0.0.255) `&]_[*@3 out], [_^Stream^ Stream][@(0.0.255) `&
+]_[*@3 in], [_^int64^ int64]_[*@3 size], [_^Gate2^ Gate2]<[_^int64^ int64], 
+[_^int64^ int64]>_[*@3 progress]_`=_[@(0.0.255) false], [@(0.0.255) bool]_[*@3 hdr]_`=_[@(0.0.255) t
+rue])&]
 [s5;:ZDecompress`(Stream`&`,Stream`&`,int64`,Gate2`<int64`,int64`>`): [_^int64^ int64]_
 [* ZDecompress]([_^Stream^ Stream][@(0.0.255) `&]_[*@3 out], [_^Stream^ Stream][@(0.0.255) `&
 ]_[*@3 in], [_^int64^ int64]_[*@3 size], [_^Gate2^ Gate2]<[_^int64^ int64], 
@@ -168,7 +176,9 @@ memory [%-*@3 data][%- , ][%-*@3 len] or input string [%-*@3 s] to output
 stream [%-*@3 out] (in this case returns a number of bytes written 
 or negative integer to signal error) or into String return value 
 (returns IsVoid String on error). [%-*@3 progress] can be used 
-to track progress of operation, returning true cancels operation.&]
+to track progress of operation, returning true cancels operation. 
+Parameter [%-*@3 hdr] can be used to switch`-off zlib header (see 
+zlib documentation for details).&]
 [s3;%% &]
 [s4;%% &]
 [s5;:GZCompress`(Stream`&`,Stream`&`,int64`,Gate2`<int64`,int64`>`): [_^int64^ int64]_[* G
diff --git a/uppsrc/Core/z.cpp b/uppsrc/Core/z.cpp
index 3531035b1..90aeaf7b7 100644
--- a/uppsrc/Core/z.cpp
+++ b/uppsrc/Core/z.cpp
@@ -346,14 +346,14 @@ int64 zPress(Stream& out, Stream& in, int64 size, Gate2<int64, int64> progress,
 	return r;
 }
 
-int64 ZCompress(Stream& out, Stream& in, int64 size, Gate2<int64, int64> progress)
+int64 ZCompress(Stream& out, Stream& in, int64 size, Gate2<int64, int64> progress, bool hdr)
 {
-	return zPress(out, in, size, progress, false, true);
+	return zPress(out, in, size, progress, false, true, NULL, hdr);
 }
 
-int64 ZDecompress(Stream& out, Stream& in, int64 size, Gate2<int64, int64> progress)
+int64 ZDecompress(Stream& out, Stream& in, int64 size, Gate2<int64, int64> progress, bool hdr)
 {
-	return zPress(out, in, size, progress, false, false);
+	return zPress(out, in, size, progress, false, false, NULL, hdr);
 }
 
 int64 ZCompress(Stream& out, Stream& in, Gate2<int64, int64> progress)
diff --git a/uppsrc/Core/z.h b/uppsrc/Core/z.h
index e92788852..a781f2144 100644
--- a/uppsrc/Core/z.h
+++ b/uppsrc/Core/z.h
@@ -73,12 +73,12 @@ public:
 	~Zlib();
 };
 
-int64  ZCompress(Stream& out, Stream& in, int64 size, Gate2<int64, int64> progress = false);
+int64  ZCompress(Stream& out, Stream& in, int64 size, Gate2<int64, int64> progress = false, bool hdr = true);
 int64  ZCompress(Stream& out, Stream& in, Gate2<int64, int64> progress = false);
 String ZCompress(const void *data, int64 len, Gate2<int64, int64> progress = false);
 String ZCompress(const String& s, Gate2<int64, int64> progress = false);
 
-int64  ZDecompress(Stream& out, Stream& in, int64 size, Gate2<int64, int64> progress = false);
+int64  ZDecompress(Stream& out, Stream& in, int64 size, Gate2<int64, int64> progress = false, bool hdr = true);
 int64  ZDecompress(Stream& out, Stream& in, Gate2<int64, int64> progress = false);
 String ZDecompress(const void *data, int64 len, Gate2<int64, int64> progress = false);
 String ZDecompress(const String& s, Gate2<int64, int64> progress = false);