diff -Naur a/libpurple/http.c b/libpurple/http.c
--- a/libpurple/http.c
+++ b/libpurple/http.c
@@ -29,6 +29,11 @@
 #include "proxy.h"
 #include "purple-socket.h"
 
+#include <zlib.h>
+#ifndef z_const
+#define z_const
+#endif
+
 #define PURPLE_HTTP_URL_CREDENTIALS_CHARS "a-z0-9.,~_/*!&%?=+\\^-"
 #define PURPLE_HTTP_MAX_RECV_BUFFER_LEN 10240
 #define PURPLE_HTTP_MAX_READ_BUFFER_LEN 10240
@@ -212,7 +217,7 @@
 struct _PurpleHttpGzStream
 {
 	gboolean failed;
-	GZlibDecompressor *decompressor;
+	z_stream zs;
 	gsize max_output;
 	gsize decompressed;
 	GString *pending;
@@ -360,14 +365,19 @@
 purple_http_gz_new(gsize max_output, gboolean is_deflate)
 {
 	PurpleHttpGzStream *gzs = g_new0(PurpleHttpGzStream, 1);
-	GZlibCompressorFormat format;
+	int windowBits;
 
 	if (is_deflate)
-		format = G_ZLIB_COMPRESSOR_FORMAT_RAW;
+		windowBits = -MAX_WBITS;
 	else /* is gzip */
-		format = G_ZLIB_COMPRESSOR_FORMAT_GZIP;
+		windowBits = MAX_WBITS + 32;
+
+	if (inflateInit2(&gzs->zs, windowBits) != Z_OK) {
+		purple_debug_error("http", "Cannot initialize zlib stream\n");
+		g_free(gzs);
+		return NULL;
+	}
 
-	gzs->decompressor = g_zlib_decompressor_new(format);
 	gzs->max_output = max_output;
 
 	return gzs;
@@ -379,6 +389,7 @@
 	const gchar *compressed_buff;
 	gsize compressed_len;
 	GString *ret;
+	z_stream *zs;
 
 	g_return_val_if_fail(gzs != NULL, NULL);
 	g_return_val_if_fail(buf != NULL, NULL);
@@ -386,6 +397,8 @@
 	if (gzs->failed)
 		return NULL;
 
+	zs = &gzs->zs;
+
 	if (gzs->pending) {
 		g_string_append_len(gzs->pending, buf, len);
 		compressed_buff = gzs->pending->str;
@@ -395,26 +408,22 @@
 		compressed_len = len;
 	}
 
+	zs->next_in = (z_const Bytef*)compressed_buff;
+	zs->avail_in = compressed_len;
+
 	ret = g_string_new(NULL);
-	while (compressed_len > 0) {
-		GConverterResult gzres;
+	while (zs->avail_in > 0) {
+		int gzres;
 		gchar decompressed_buff[PURPLE_HTTP_GZ_BUFF_LEN];
-		gsize decompressed_len = 0;
-		gsize bytes_read = 0;
-		GError *error = NULL;
-
-		gzres = g_converter_convert(G_CONVERTER(gzs->decompressor),
-			       compressed_buff, compressed_len,
-		       	       decompressed_buff, sizeof(decompressed_buff),
-			       G_CONVERTER_NO_FLAGS,
-			       &bytes_read,
-			       &decompressed_len,
-			       &error);
+		gsize decompressed_len;
 
-		compressed_buff += bytes_read;
-		compressed_len -= bytes_read;
+		zs->next_out = (Bytef*)decompressed_buff;
+		zs->avail_out = sizeof(decompressed_buff);
+		decompressed_len = zs->avail_out = sizeof(decompressed_buff);
+		gzres = inflate(zs, Z_FULL_FLUSH);
+		decompressed_len -= zs->avail_out;
 
-		if (gzres == G_CONVERTER_CONVERTED || G_CONVERTER_FINISHED) {
+		if (gzres == Z_OK || gzres == Z_STREAM_END) {
 			if (decompressed_len == 0)
 				break;
 			if (gzs->decompressed + decompressed_len >=
@@ -424,18 +433,17 @@
 					" decompressed data is reached\n");
 				decompressed_len = gzs->max_output -
 					gzs->decompressed;
-				gzres = G_CONVERTER_FINISHED;
+				gzres = Z_STREAM_END;
 			}
 			gzs->decompressed += decompressed_len;
 			g_string_append_len(ret, decompressed_buff,
 				decompressed_len);
-			if (gzres == G_CONVERTER_FINISHED)
+			if (gzres == Z_STREAM_END)
 				break;
 		} else {
 			purple_debug_error("http",
 				"Decompression failed (%d): %s\n", gzres,
-				error->message);
-			g_clear_error(&error);
+				zs->msg);
 			gzs->failed = TRUE;
 			return NULL;
 		}
@@ -446,9 +454,9 @@
 		gzs->pending = NULL;
 	}
 
-	if (compressed_len > 0) {
-		gzs->pending = g_string_new_len(compressed_buff,
-			compressed_len);
+	if (zs->avail_in > 0) {
+		gzs->pending = g_string_new_len((gchar*)zs->next_in,
+			zs->avail_in);
 	}
 
 	return ret;
@@ -459,7 +467,7 @@
 {
 	if (gzs == NULL)
 		return;
-	g_object_unref(gzs->decompressor);
+	inflateEnd(&gzs->zs);
 	if (gzs->pending)
 		g_string_free(gzs->pending, TRUE);
 	g_free(gzs);