diff --git a/ChangeLog b/ChangeLog
index c2a30dfba..b512c318a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,4 @@
+	* add build option to disable share-mode
 	* support validation of HTTPS trackers
 	* deprecate strict super seeding mode
 	* make UPnP port-mapping lease duration configurable
diff --git a/Jamfile b/Jamfile
index 28a1542e3..0ec171f47 100644
--- a/Jamfile
+++ b/Jamfile
@@ -442,6 +442,9 @@ feature.compose <test-coverage>on : <cflags>--coverage <linkflags>--coverage ;
 feature predictive-pieces : on off : composite propagated ;
 feature.compose <predictive-pieces>off : <define>TORRENT_DISABLE_PREDICTIVE_PIECES ;
 
+feature share-mode : on off : composite propagated ;
+feature.compose <share-mode>off : <define>TORRENT_DISABLE_SHARE_MODE ;
+
 feature streaming : on off : composite propagated ;
 feature.compose <streaming>off : <define>TORRENT_DISABLE_STREAMING ;
 
diff --git a/docs/building.rst b/docs/building.rst
index b7f9e2800..64821a21d 100644
--- a/docs/building.rst
+++ b/docs/building.rst
@@ -387,6 +387,9 @@ Build features:
 | ``super-seeding``        | * ``on`` - enable super seeding feature. (default) |
 |                          | * ``off`` - disable super seeding feature          |
 +--------------------------+----------------------------------------------------+
+| ``share-mode``           | * ``on`` - enable share-mode feature. (default)    |
+|                          | * ``off`` - disable share-mode feature             |
++--------------------------+----------------------------------------------------+
 | ``predictive-pieces``    | * ``on`` - enable predictive piece announce        |
 |                          |   feature. i.e.                                    |
 |                          |   settings_pack::predictive_piece_announce         |
@@ -545,6 +548,10 @@ defines you can use to control the build.
 |                                        | seeding. The settings will exist, but will not  |
 |                                        | have an effect, when this macro is defined.     |
 +----------------------------------------+-------------------------------------------------+
+| ``TORRENT_DISABLE_SHARE_MODE``         | This macro will disable support for share-mode. |
+|                                        | i.e. the mode to maximize upload/download       |
+|                                        | ratio for a torrent.                            |
++----------------------------------------+-------------------------------------------------+
 | ``TORRENT_DISABLE_MUTABLE_TORRENTS``   | Disables mutable torrent support (`BEP 38`_)    |
 +----------------------------------------+-------------------------------------------------+
 | ``TORRENT_DISABLE_STREAMING``          | Disables set_piece_deadline() and associated    |
diff --git a/include/libtorrent/peer_connection.hpp b/include/libtorrent/peer_connection.hpp
index 25c11afd9..3e46ac423 100644
--- a/include/libtorrent/peer_connection.hpp
+++ b/include/libtorrent/peer_connection.hpp
@@ -386,8 +386,10 @@ namespace aux {
 		bool is_seed() const;
 		int num_have_pieces() const { return m_num_pieces; }
 
+#ifndef TORRENT_DISABLE_SHARE_MODE
 		void set_share_mode(bool m);
 		bool share_mode() const { return m_share_mode; }
+#endif
 
 		void set_upload_only(bool u);
 		bool upload_only() const { return m_upload_only; }
@@ -1105,8 +1107,10 @@ namespace aux {
 		// at a time.
 		bool m_request_large_blocks:1;
 
+#ifndef TORRENT_DISABLE_SHARE_MODE
 		// set to true if this peer is in share mode
 		bool m_share_mode:1;
+#endif
 
 		// set to true when this peer is only uploading
 		bool m_upload_only:1;
diff --git a/include/libtorrent/torrent.hpp b/include/libtorrent/torrent.hpp
index bfa173584..11e946cbf 100644
--- a/include/libtorrent/torrent.hpp
+++ b/include/libtorrent/torrent.hpp
@@ -287,8 +287,10 @@ namespace libtorrent {
 		// effectively paused as well.
 		bool m_session_paused:1;
 
+#ifndef TORRENT_DISABLE_SHARE_MODE
 		// this is set when the torrent is in share-mode
 		bool m_share_mode:1;
+#endif
 
 		// this is true if we have all pieces. If it's false,
 		// it means we either don't have any pieces, or, if
@@ -411,11 +413,13 @@ namespace libtorrent {
 		void start_announcing();
 		void stop_announcing();
 
-		void send_share_mode();
 		void send_upload_only();
 
+#ifndef TORRENT_DISABLE_SHARE_MODE
+		void send_share_mode();
 		void set_share_mode(bool s);
 		bool share_mode() const { return m_share_mode; }
+#endif
 
 		// TODO: make graceful pause also finish all sending blocks
 		// before disconnecting
@@ -777,7 +781,9 @@ namespace libtorrent {
 // --------------------------------------------
 		// PIECE MANAGEMENT
 
+#ifndef TORRENT_DISABLE_SHARE_MODE
 		void recalc_share_mode();
+#endif
 
 #ifndef TORRENT_DISABLE_SUPERSEEDING
 		bool super_seeding() const
diff --git a/src/bt_peer_connection.cpp b/src/bt_peer_connection.cpp
index 27ab2b451..fbd37672a 100644
--- a/src/bt_peer_connection.cpp
+++ b/src/bt_peer_connection.cpp
@@ -298,7 +298,9 @@ namespace {
 		// will send their bitfield when the handshake
 		// is done
 		std::shared_ptr<torrent> t = associated_torrent().lock();
+#ifndef TORRENT_DISABLE_SHARE_MODE
 		if (!t->share_mode())
+#endif
 		{
 			bool const upload_only_enabled = t->is_upload_only()
 #ifndef TORRENT_DISABLE_SUPERSEEDING
@@ -1608,6 +1610,7 @@ namespace {
 			return;
 		}
 
+#ifndef TORRENT_DISABLE_SHARE_MODE
 		if (extended_id == share_mode_msg)
 		{
 			if (!m_recv_buffer.packet_finished()) return;
@@ -1627,6 +1630,7 @@ namespace {
 			set_share_mode(sm);
 			return;
 		}
+#endif // TORRENT_DISABLE_SHARE_MODE
 
 		if (extended_id == holepunch_msg)
 		{
@@ -1751,9 +1755,11 @@ namespace {
 		if (root.dict_find_int_value("upload_only", 0))
 			set_upload_only(true);
 
+#ifndef TORRENT_DISABLE_SHARE_MODE
 		if (m_settings.get_bool(settings_pack::support_share_mode)
 			&& root.dict_find_int_value("share_mode", 0))
 			set_share_mode(true);
+#endif
 
 		auto const myip = root.dict_find_string_value("yourip");
 		if (!myip.empty())
@@ -1786,7 +1792,10 @@ namespace {
 		// disconnect it
 		if (t->is_finished() && upload_only()
 			&& m_settings.get_bool(settings_pack::close_redundant_connections)
-			&& !t->share_mode())
+#ifndef TORRENT_DISABLE_SHARE_MODE
+			&& !t->share_mode()
+#endif
+			)
 			disconnect(errors::upload_upload_connection, operation_t::bittorrent);
 
 		stats_counters().inc_stats_counter(counters::num_incoming_ext_handshake);
@@ -1888,7 +1897,7 @@ namespace {
 	{
 		INVARIANT_CHECK;
 
-#if TORRENT_USE_ASSERTS
+#if TORRENT_USE_ASSERTS && !defined TORRENT_DISABLE_SHARE_MODE
 		std::shared_ptr<torrent> t = associated_torrent().lock();
 		TORRENT_ASSERT(!t->share_mode());
 #endif
@@ -1909,6 +1918,7 @@ namespace {
 		stats_counters().inc_stats_counter(counters::num_outgoing_extended);
 	}
 
+#ifndef TORRENT_DISABLE_SHARE_MODE
 	void bt_peer_connection::write_share_mode()
 	{
 		INVARIANT_CHECK;
@@ -1924,6 +1934,7 @@ namespace {
 
 		stats_counters().inc_stats_counter(counters::num_outgoing_extended);
 	}
+#endif
 
 	void bt_peer_connection::write_keepalive()
 	{
@@ -2125,8 +2136,10 @@ namespace {
 
 		m["upload_only"] = upload_only_msg;
 		m["ut_holepunch"] = holepunch_msg;
+#ifndef TORRENT_DISABLE_SHARE_MODE
 		if (m_settings.get_bool(settings_pack::support_share_mode))
 			m["share_mode"] = share_mode_msg;
+#endif
 		m["lt_donthave"] = dont_have_msg;
 
 		int complete_ago = -1;
@@ -2143,7 +2156,9 @@ namespace {
 		// upload-only. If we do, we may be disconnected before we receive the
 		// metadata.
 		if (t->is_upload_only()
+#ifndef TORRENT_DISABLE_SHARE_MODE
 			&& !t->share_mode()
+#endif
 			&& t->valid_metadata()
 #ifndef TORRENT_DISABLE_SUPERSEEDING
 			&& !t->super_seeding()
@@ -2153,9 +2168,11 @@ namespace {
 			handshake["upload_only"] = 1;
 		}
 
+#ifndef TORRENT_DISABLE_SHARE_MODE
 		if (m_settings.get_bool(settings_pack::support_share_mode)
 			&& t->share_mode())
 			handshake["share_mode"] = 1;
+#endif
 
 #ifndef TORRENT_DISABLE_EXTENSIONS
 		// loop backwards, to make the first extension be the last
diff --git a/src/peer_connection.cpp b/src/peer_connection.cpp
index 2a2446138..6df960463 100644
--- a/src/peer_connection.cpp
+++ b/src/peer_connection.cpp
@@ -143,7 +143,9 @@ namespace libtorrent {
 		, m_failed(false)
 		, m_connected(pack.tor.expired())
 		, m_request_large_blocks(false)
+#ifndef TORRENT_DISABLE_SHARE_MODE
 		, m_share_mode(false)
+#endif
 		, m_upload_only(false)
 		, m_bitfield_received(false)
 		, m_no_download(false)
@@ -2260,8 +2262,10 @@ namespace libtorrent {
 		// metadata from us
 		if (!t->valid_metadata() || !has_metadata()) return false;
 
+#ifndef TORRENT_DISABLE_SHARE_MODE
 		// don't close connections in share mode, we don't know if we need them
 		if (t->share_mode()) return false;
+#endif
 
 		if (m_upload_only && t->is_upload_only()
 			&& can_disconnect(errors::upload_upload_connection))
@@ -5141,7 +5145,9 @@ namespace libtorrent {
 		INVARIANT_CHECK;
 #endif
 
+#ifndef TORRENT_DISABLE_SHARE_MODE
 		bool sent_a_piece = false;
+#endif
 		std::shared_ptr<torrent> t = m_torrent.lock();
 		if (!t || t->is_aborted() || m_requests.empty()) return;
 
@@ -5251,7 +5257,9 @@ namespace libtorrent {
 					, "piece: %d s: %x l: %x", static_cast<int>(r.piece), r.start, r.length);
 #endif
 				m_reading_bytes += r.length;
+#ifndef TORRENT_DISABLE_SHARE_MODE
 				sent_a_piece = true;
+#endif
 
 				// the callback function may be called immediately, instead of being posted
 
@@ -5273,8 +5281,10 @@ namespace libtorrent {
 			--i;
 		}
 
+#ifndef TORRENT_DISABLE_SHARE_MODE
 		if (t->share_mode() && sent_a_piece)
 			t->recalc_share_mode();
+#endif
 	}
 
 	// this is called when a previously unchecked piece has been
@@ -6419,7 +6429,10 @@ namespace libtorrent {
 
 		// in share mode we don't close redundant connections
 		if (m_settings.get_bool(settings_pack::close_redundant_connections)
-			&& !t->share_mode())
+#ifndef TORRENT_DISABLE_SHARE_MODE
+			&& !t->share_mode()
+#endif
+			)
 		{
 			bool const ok_to_disconnect =
 				can_disconnect(errors::upload_upload_connection)
@@ -6590,6 +6603,7 @@ namespace libtorrent {
 			&& m_num_pieces > 0 && t && t->valid_metadata();
 	}
 
+#ifndef TORRENT_DISABLE_SHARE_MODE
 	void peer_connection::set_share_mode(bool u)
 	{
 		TORRENT_ASSERT(is_single_thread());
@@ -6598,6 +6612,7 @@ namespace libtorrent {
 
 		m_share_mode = u;
 	}
+#endif
 
 	void peer_connection::set_upload_only(bool u)
 	{
diff --git a/src/torrent.cpp b/src/torrent.cpp
index cdb3e59de..088482911 100644
--- a/src/torrent.cpp
+++ b/src/torrent.cpp
@@ -158,7 +158,9 @@ bool is_downloading_state(int const st)
 		, m_abort(false)
 		, m_paused(p.flags & torrent_flags::paused)
 		, m_session_paused(session_paused)
+#ifndef TORRENT_DISABLE_SHARE_MODE
 		, m_share_mode(p.flags & torrent_flags::share_mode)
+#endif
 		, m_have_all(false)
 		, m_graceful_pause_mode(false)
 		, m_state_subscription(p.flags & torrent_flags::update_subscribe)
@@ -689,7 +691,11 @@ bool is_downloading_state(int const st)
 				, download_limit()
 				, m_seed_mode ? "seed-mode " : ""
 				, m_upload_mode ? "upload-mode " : ""
+#ifndef TORRENT_DISABLE_SHARE_MODE
 				, m_share_mode ? "share-mode " : ""
+#else
+				, ""
+#endif
 				, m_apply_ip_filter ? "apply-ip-filter " : ""
 				, m_paused ? "paused " : ""
 				, m_auto_managed ? "auto-managed " : ""
@@ -920,6 +926,7 @@ bool is_downloading_state(int const st)
 		m_ses.disk_thread().submit_jobs();
 	}
 
+#ifndef TORRENT_DISABLE_SHARE_MODE
 	void torrent::send_share_mode()
 	{
 #ifndef TORRENT_DISABLE_EXTENSIONS
@@ -932,11 +939,15 @@ bool is_downloading_state(int const st)
 		}
 #endif
 	}
+#endif // TORRENT_DISABLE_SHARE_MODE
 
 	void torrent::send_upload_only()
 	{
 #ifndef TORRENT_DISABLE_EXTENSIONS
+
+#ifndef TORRENT_DISABLE_SHARE_MODE
 		if (share_mode()) return;
+#endif
 #ifndef TORRENT_DISABLE_SUPERSEEDING
 		if (super_seeding()) return;
 #endif
@@ -964,7 +975,7 @@ bool is_downloading_state(int const st)
 			p->send_not_interested();
 			p->send_upload_only(upload_only_enabled);
 		}
-#endif
+#endif // TORRENT_DISABLE_EXTENSIONS
 	}
 
 	torrent_flags_t torrent::flags() const
@@ -974,8 +985,10 @@ bool is_downloading_state(int const st)
 			ret |= torrent_flags::seed_mode;
 		if (m_upload_mode)
 			ret |= torrent_flags::upload_mode;
+#ifndef TORRENT_DISABLE_SHARE_MODE
 		if (m_share_mode)
 			ret |= torrent_flags::share_mode;
+#endif
 		if (m_apply_ip_filter)
 			ret |= torrent_flags::apply_ip_filter;
 		if (is_torrent_paused())
@@ -1009,8 +1022,10 @@ bool is_downloading_state(int const st)
 		}
 		if (mask & torrent_flags::upload_mode)
 			set_upload_mode(bool(flags & torrent_flags::upload_mode));
+#ifndef TORRENT_DISABLE_SHARE_MODE
 		if (mask & torrent_flags::share_mode)
 			set_share_mode(bool(flags & torrent_flags::share_mode));
+#endif
 		if (mask & torrent_flags::apply_ip_filter)
 			set_apply_ip_filter(bool(flags & torrent_flags::apply_ip_filter));
 		if (mask & torrent_flags::paused)
@@ -1038,6 +1053,7 @@ bool is_downloading_state(int const st)
 			m_enable_pex = !bool(flags & torrent_flags::disable_pex);
 	}
 
+#ifndef TORRENT_DISABLE_SHARE_MODE
 	void torrent::set_share_mode(bool s)
 	{
 		if (s == m_share_mode) return;
@@ -1056,6 +1072,7 @@ bool is_downloading_state(int const st)
 			prioritize_files(aux::vector<download_priority_t, file_index_t>(num_files, dont_download));
 		}
 	}
+#endif // TORRENT_DISABLE_SHARE_MODE
 
 	void torrent::set_upload_mode(bool b)
 	{
@@ -1819,12 +1836,14 @@ bool is_downloading_state(int const st)
 
 		construct_storage();
 
+#ifndef TORRENT_DISABLE_SHARE_MODE
 		if (m_share_mode && valid_metadata())
 		{
 			// in share mode, all pieces have their priorities initialized to 0
 			m_file_priority.clear();
 			m_file_priority.resize(m_torrent_file->num_files(), dont_download);
 		}
+#endif
 
 		// it's important to initialize the peers early, because this is what will
 		// fix up their have-bitmasks to have the correct size
@@ -3973,8 +3992,10 @@ bool is_downloading_state(int const st)
 
 			m_last_download = aux::time_now32();
 
+#ifndef TORRENT_DISABLE_SHARE_MODE
 			if (m_share_mode)
 				recalc_share_mode();
+#endif
 		}
 	}
 
@@ -5072,8 +5093,10 @@ bool is_downloading_state(int const st)
 		if (m_file_priority != prios)
 		{
 			m_file_priority = std::move(prios);
+#ifndef TORRENT_DISABLE_SHARE_MODE
 			if (m_share_mode)
 				recalc_share_mode();
+#endif
 		}
 
 		if (err)
@@ -6813,8 +6836,10 @@ bool is_downloading_state(int const st)
 			return false;
 		}
 
+#ifndef TORRENT_DISABLE_SHARE_MODE
 		if (m_share_mode)
 			recalc_share_mode();
+#endif
 
 		return peerinfo->connection != nullptr;
 	}
@@ -7137,8 +7162,10 @@ bool is_downloading_state(int const st)
 		if (m_peer_list) m_peer_list->check_invariant();
 #endif
 
+#ifndef TORRENT_DISABLE_SHARE_MODE
 		if (m_share_mode)
 			recalc_share_mode();
+#endif
 
 		// once we add the peer to our m_connections list, we can't throw an
 		// exception. That will end up violating an invariant between the session,
@@ -9339,6 +9366,7 @@ bool is_downloading_state(int const st)
 		}
 	}
 
+#ifndef TORRENT_DISABLE_SHARE_MODE
 	void torrent::recalc_share_mode()
 	{
 		TORRENT_ASSERT(share_mode());
@@ -9475,6 +9503,7 @@ bool is_downloading_state(int const st)
 		update_peer_interest(was_finished);
 		update_want_peers();
 	}
+#endif // TORRENT_DISABLE_SHARE_MODE
 
 	void torrent::sent_bytes(int const bytes_payload, int const bytes_protocol)
 	{
@@ -10720,7 +10749,11 @@ bool is_downloading_state(int const st)
 #endif
 
 #if TORRENT_ABI_VERSION == 1
+#ifndef TORRENT_DISABLE_SHARE_MODE
 		st->share_mode = m_share_mode;
+#else
+		st->share_mode = false;
+#endif
 		st->upload_mode = m_upload_mode;
 #endif
 		st->up_bandwidth_queue = 0;
diff --git a/src/torrent_handle.cpp b/src/torrent_handle.cpp
index 0c36006b0..dfb166478 100644
--- a/src/torrent_handle.cpp
+++ b/src/torrent_handle.cpp
@@ -310,7 +310,12 @@ namespace libtorrent {
 	{ async_call(&torrent::set_upload_mode, b); }
 
 	void torrent_handle::set_share_mode(bool b) const
-	{ async_call(&torrent::set_share_mode, b); }
+	{
+		TORRENT_UNUSED(b);
+#ifndef TORRENT_DISABLE_SHARE_MODE
+		async_call(&torrent::set_share_mode, b);
+#endif
+	}
 
 	void torrent_handle::apply_ip_filter(bool b) const
 	{ async_call(&torrent::set_apply_ip_filter, b); }
diff --git a/test/test_fast_extension.cpp b/test/test_fast_extension.cpp
index cddc50882..3735d9748 100644
--- a/test/test_fast_extension.cpp
+++ b/test/test_fast_extension.cpp
@@ -926,7 +926,9 @@ TORRENT_TEST(extension_handshake)
 
 	// these extensions are built-in
 	TEST_CHECK(extensions["m"]["lt_donthave"].integer() != 0);
+#ifndef TORRENT_DISABLE_SHARE_MODE
 	TEST_CHECK(extensions["m"]["share_mode"].integer() != 0);
+#endif
 	TEST_CHECK(extensions["m"]["upload_only"].integer() != 0);
 	TEST_CHECK(extensions["m"]["ut_holepunch"].integer() != 0);
 
diff --git a/test/test_flags.cpp b/test/test_flags.cpp
index d7498655c..829fc8baf 100644
--- a/test/test_flags.cpp
+++ b/test/test_flags.cpp
@@ -115,6 +115,7 @@ TORRENT_TEST(flag_upload_mode)
 	test_unset_after_add(torrent_flags::upload_mode);
 }
 
+#ifndef TORRENT_DISABLE_SHARE_MODE
 TORRENT_TEST(flag_share_mode)
 {
 	// share-mode
@@ -122,6 +123,7 @@ TORRENT_TEST(flag_share_mode)
 	test_set_after_add(torrent_flags::share_mode);
 	test_unset_after_add(torrent_flags::share_mode);
 }
+#endif
 
 TORRENT_TEST(flag_apply_ip_filter)
 {
diff --git a/test/test_resume.cpp b/test/test_resume.cpp
index 9a7847d3d..23367357e 100644
--- a/test/test_resume.cpp
+++ b/test/test_resume.cpp
@@ -602,6 +602,7 @@ TORRENT_TEST(file_priorities_override_resume_deprecated)
 	TEST_EQUAL(file_priorities[2], 3);
 }
 
+#ifndef TORRENT_DISABLE_SHARE_MODE
 TORRENT_TEST(file_priorities_resume_share_mode_deprecated)
 {
 	// in share mode file priorities should always be 0
@@ -627,6 +628,7 @@ TORRENT_TEST(file_priorities_share_mode_deprecated)
 	TEST_EQUAL(file_priorities[1], 0);
 	TEST_EQUAL(file_priorities[2], 0);
 }
+#endif
 
 TORRENT_TEST(resume_save_load_deprecated)
 {
@@ -815,6 +817,7 @@ TORRENT_TEST(upload_mode_deprecated)
 	TEST_EQUAL(s.uploads_limit, 1346);
 }
 
+#ifndef TORRENT_DISABLE_SHARE_MODE
 TORRENT_TEST(share_mode_deprecated)
 {
 	lt::session ses(settings());
@@ -831,6 +834,7 @@ TORRENT_TEST(share_mode_deprecated)
 	TEST_EQUAL(s.connections_limit, 2);
 	TEST_EQUAL(s.uploads_limit, 1);
 }
+#endif
 
 TORRENT_TEST(auto_managed_deprecated)
 {
@@ -924,6 +928,7 @@ TORRENT_TEST(file_priorities_default)
 	TEST_EQUAL(file_priorities[2], 4_pri);
 }
 
+#ifndef TORRENT_DISABLE_SHARE_MODE
 TORRENT_TEST(file_priorities_resume_share_mode)
 {
 	// in share mode file priorities should always be 0
@@ -949,6 +954,7 @@ TORRENT_TEST(file_priorities_share_mode)
 	TEST_EQUAL(file_priorities[1], 0_pri);
 	TEST_EQUAL(file_priorities[2], 0_pri);
 }
+#endif
 
 namespace {
 
@@ -1418,6 +1424,7 @@ TORRENT_TEST(upload_mode)
 	TEST_EQUAL(s.uploads_limit, 1346);
 }
 
+#ifndef TORRENT_DISABLE_SHARE_MODE
 TORRENT_TEST(share_mode)
 {
 	lt::session ses(settings());
@@ -1433,6 +1440,7 @@ TORRENT_TEST(share_mode)
 	TEST_EQUAL(s.connections_limit, 1345);
 	TEST_EQUAL(s.uploads_limit, 1346);
 }
+#endif
 
 TORRENT_TEST(auto_managed)
 {