diff --git a/README.md b/README.md
index f897a24bf..caa3d0267 100755
--- a/README.md
+++ b/README.md
@@ -295,6 +295,7 @@ Remark:
 
 ## Releases
 
+* 2021-06-26, [Release v2.0-r9](https://github.com/ossrs/srs/releases/tag/v2.0-r9), 2.0 release9, 2.0.273, 87552 lines.
 * 2020-01-25, [Release v2.0-r8][r2.0r8], 2.0 release8, 2.0.272, 87292 lines.
 * 2018-11-29, [Release v2.0-r7][r2.0r7], 2.0 release7, 2.0.265, 86994 lines.
 * 2018-10-28, [Release v2.0-r6][r2.0r6], 2.0 release6, 2.0.263, 86994 lines.
@@ -339,6 +340,10 @@ Remark:
 
 ## History
 
+* <strong>v2.0, 2021-06-26, [2.0 release9(2.0.274)](https://github.com/ossrs/srs/releases/tag/v2.0-r10) released. 87575 lines.</strong>
+* v2.0, 2021-07-04, For [#2424](https://github.com/ossrs/srs/issues/2424), use srandom/random to generate. 2.0.274
+* <strong>v2.0, 2021-06-26, [2.0 release9(2.0.273)](https://github.com/ossrs/srs/releases/tag/v2.0-r9) released. 87552 lines.</strong>
+* v2.0, 2021-06-25, For [#2424](https://github.com/ossrs/srs/issues/2424), query the latest available version. 2.0.273
 * <strong>v2.0, 2020-01-25, [2.0 release8(2.0.272)][r2.0r8] released. 87292 lines.</strong>
 * v2.0, 2020-01-08, Merge [#1554][bug #1554], support logrotate copytruncate. 2.0.272
 * v2.0, 2020-01-05, Merge [#1551][bug #1551], fix memory leak in RTSP stack. 2.0.270
diff --git a/trunk/conf/full.conf b/trunk/conf/full.conf
index a8f12aa10..4c088705e 100644
--- a/trunk/conf/full.conf
+++ b/trunk/conf/full.conf
@@ -63,6 +63,11 @@ work_dir ./;
 # default: off
 asprocess off;
 
+# Query the latest available version of SRS, write a log to notice user to upgrade.
+# @see https://github.com/ossrs/srs/issues/2424
+# Default: on
+query_latest_version on;
+
 #############################################################################################
 # heartbeat/stats sections
 #############################################################################################
diff --git a/trunk/configure b/trunk/configure
index eecba9cab..68fab4ba6 100755
--- a/trunk/configure
+++ b/trunk/configure
@@ -179,7 +179,7 @@ if [ $SRS_EXPORT_LIBRTMP_PROJECT = NO ]; then
             "srs_app_heartbeat" "srs_app_empty" "srs_app_http_client" "srs_app_http_static"
             "srs_app_recv_thread" "srs_app_security" "srs_app_statistic" "srs_app_hds"
             "srs_app_mpegts_udp" "srs_app_rtsp" "srs_app_listener" "srs_app_async_call"
-            "srs_app_caster_flv")
+            "srs_app_caster_flv" "srs_app_latest_version")
     DEFINES=""
     # add each modules for app
     for SRS_MODULE in ${SRS_MODULES[*]}; do
diff --git a/trunk/src/app/srs_app_config.cpp b/trunk/src/app/srs_app_config.cpp
index 9ee6c668c..1361a27fc 100644
--- a/trunk/src/app/srs_app_config.cpp
+++ b/trunk/src/app/srs_app_config.cpp
@@ -2212,6 +2212,18 @@ bool SrsConfig::get_asprocess()
     return SRS_CONF_PERFER_FALSE(conf->arg0());
 }
 
+bool SrsConfig::whether_query_latest_version()
+{
+    static bool DEFAULT = true;
+
+    SrsConfDirective* conf = root->get("query_latest_version");
+    if (!conf) {
+        return DEFAULT;
+    }
+
+    return SRS_CONF_PERFER_TRUE(conf->arg0());
+}
+
 vector<SrsConfDirective*> SrsConfig::get_stream_casters()
 {
     srs_assert(root);
diff --git a/trunk/src/app/srs_app_config.hpp b/trunk/src/app/srs_app_config.hpp
index 89f3922d6..dff6c91e2 100644
--- a/trunk/src/app/srs_app_config.hpp
+++ b/trunk/src/app/srs_app_config.hpp
@@ -386,6 +386,8 @@ public:
     virtual std::string         get_work_dir();
     // whether use asprocess mode.
     virtual bool                get_asprocess();
+    // Whether query the latest available version of SRS.
+    virtual bool whether_query_latest_version();
 // stream_caster section
 public:
     /**
diff --git a/trunk/src/app/srs_app_ingest.cpp b/trunk/src/app/srs_app_ingest.cpp
index a30069ba3..a46615595 100644
--- a/trunk/src/app/srs_app_ingest.cpp
+++ b/trunk/src/app/srs_app_ingest.cpp
@@ -35,6 +35,7 @@ using namespace std;
 #include <srs_app_pithy_print.hpp>
 #include <srs_kernel_utility.hpp>
 #include <srs_app_utility.hpp>
+#include <srs_rtmp_utility.hpp>
 
 // when error, ingester sleep for a while and retry.
 // ingest never sleep a long time, for we must start the stream ASAP.
@@ -436,7 +437,7 @@ void SrsIngester::show_ingest_log_message()
     }
     
     // random choose one ingester to report.
-    int index = rand() % (int)ingesters.size();
+    int index = srs_random() % (int)ingesters.size();
     SrsIngesterFFMPEG* ingester = ingesters.at(index);
     
     // reportable
diff --git a/trunk/src/app/srs_app_latest_version.cpp b/trunk/src/app/srs_app_latest_version.cpp
new file mode 100644
index 000000000..86438a6b8
--- /dev/null
+++ b/trunk/src/app/srs_app_latest_version.cpp
@@ -0,0 +1,176 @@
+/*
+The MIT License (MIT)
+
+Copyright (c) 2013-2015 SRS(ossrs)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+*/
+
+#include <srs_app_latest_version.hpp>
+
+#include <srs_core_autofree.hpp>
+#include <srs_kernel_error.hpp>
+#include <srs_kernel_log.hpp>
+#include <srs_kernel_utility.hpp>
+#include <srs_protocol_json.hpp>
+#include <srs_rtmp_utility.hpp>
+#include <srs_app_config.hpp>
+#include <srs_app_http_conn.hpp>
+#include <srs_app_http_client.hpp>
+#include <srs_app_utility.hpp>
+
+#include <unistd.h>
+#include <sstream>
+using namespace std;
+
+SrsLatestVersion::SrsLatestVersion()
+{
+    trd_ = new SrsEndlessThread("signal", this);
+}
+
+SrsLatestVersion::~SrsLatestVersion()
+{
+    srs_freep(trd_);
+}
+
+int SrsLatestVersion::start()
+{
+    if (!_srs_config->whether_query_latest_version()) {
+        return ERROR_SUCCESS;
+    }
+
+    char buf[16];
+    srs_random_generate(buf, sizeof(buf));
+    for (int i = 0; i < (int)sizeof(buf); i++) {
+        buf[i] = 'a' + uint8_t(buf[i])%25;
+    }
+    server_id_ = string(buf, sizeof(buf));
+
+    return trd_->start();
+}
+
+int SrsLatestVersion::cycle()
+{
+    int ret = ERROR_SUCCESS;
+
+    int64_t starttime = srs_update_system_time_ms();
+    ret = query_latest_version(); // Ignore any error.
+
+    uint64_t first_random_wait = 0;
+    srs_random_generate((char*)&first_random_wait, 8);
+    first_random_wait = (first_random_wait + starttime + getpid()) % (60 * 60); // in s.
+
+    srs_trace("Startup query id=%s, eip=%s, match=%s, stable=%s, wait=%ds, cost=%dms, ret=%d", server_id_.c_str(), srs_get_public_internet_address().c_str(), match_version_.c_str(), stable_version_.c_str(), (int)first_random_wait, (int)(srs_update_system_time_ms() - starttime), ret);
+    st_usleep(first_random_wait * 1000 * 1000);
+
+    while (true) {
+        int64_t starttime = srs_update_system_time_ms();
+        ret = query_latest_version(); // Ignore any error.
+        srs_trace("Finish query id=%s, eip=%s, match=%s, stable=%s, cost=%dms, ret=%d", server_id_.c_str(), srs_get_public_internet_address().c_str(), match_version_.c_str(), stable_version_.c_str(), (int)(srs_update_system_time_ms() - starttime), ret);
+
+        st_usleep(3600 * 1000 * 1000LL); // Every an hour.
+    }
+
+    return ret;
+}
+
+int SrsLatestVersion::query_latest_version()
+{
+    int ret = ERROR_SUCCESS;
+
+    // Generate uri and parse to object.
+    stringstream ss;
+    ss << "http://api.ossrs.net/service/v1/releases?"
+          << "version=v" << VERSION_MAJOR << "." << VERSION_MINOR << "." << VERSION_REVISION
+          << "&id=" << server_id_
+          << "&eip=" << srs_get_public_internet_address()
+          << "&ts=" << srs_get_system_time_ms();
+    string url = ss.str();
+
+    SrsHttpUri uri;
+    if ((ret = uri.initialize(url)) != ERROR_SUCCESS) {
+        srs_error("http: post failed. url=%s, ret=%d", url.c_str(), ret);
+        return ret;
+    }
+
+    // Start HTTP request and read response.
+    SrsHttpClient http;
+    if ((ret = http.initialize(uri.get_host(), uri.get_port())) != ERROR_SUCCESS) {
+        return ret;
+    }
+
+    // Path with query.
+    string path = uri.get_path();
+    path += "?";
+    path += uri.get_query();
+
+    ISrsHttpMessage* msg = NULL;
+    if ((ret = http.get(path, "", &msg)) != ERROR_SUCCESS) {
+        return ret;
+    }
+    SrsAutoFree(ISrsHttpMessage, msg);
+
+    string res;
+    int code = msg->status_code();
+    if ((ret = msg->body_read_all(res)) != ERROR_SUCCESS) {
+        return ret;
+    }
+
+    // Check the response code and content.
+    if (code != SRS_CONSTS_HTTP_OK) {
+        ret = ERROR_HTTP_STATUS_INVALID;
+        srs_error("invalid response status=%d. ret=%d", code, ret);
+        return ret;
+    }
+
+    if (res.empty()) {
+        ret = ERROR_HTTP_DATA_INVALID;
+        srs_error("invalid empty response. ret=%d", ret);
+        return ret;
+    }
+
+    // Response in json object.
+    SrsJsonAny* jres = SrsJsonAny::loads((char*)res.c_str());
+    if (!jres || !jres->is_object()) {
+        ret = ERROR_HTTP_DATA_INVALID;
+        srs_error("invalid response %s. ret=%d", res.c_str(), ret);
+        return ret;
+    }
+    SrsAutoFree(SrsJsonAny, jres);
+
+    SrsJsonObject* obj = jres->to_object();
+    SrsJsonAny* prop = NULL;
+
+    // Parse fields of response.
+    if ((prop = obj->ensure_property_string("match_version")) == NULL) {
+        ret = ERROR_RESPONSE_CODE;
+        srs_error("invalid response without match_version, ret=%d", ret);
+        return ret;
+    }
+    match_version_ = prop->to_str();
+
+    if ((prop = obj->ensure_property_string("stable_version")) == NULL) {
+        ret = ERROR_RESPONSE_CODE;
+        srs_error("invalid response without stable_version, ret=%d", ret);
+        return ret;
+    }
+    stable_version_ = prop->to_str();
+
+    return ret;
+}
+
diff --git a/trunk/src/app/srs_app_latest_version.hpp b/trunk/src/app/srs_app_latest_version.hpp
new file mode 100644
index 000000000..187c3f8f6
--- /dev/null
+++ b/trunk/src/app/srs_app_latest_version.hpp
@@ -0,0 +1,58 @@
+/*
+The MIT License (MIT)
+
+Copyright (c) 2013-2015 SRS(ossrs)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+*/
+
+#ifndef SRS_APP_LATEST_VERSION_HPP
+#define SRS_APP_LATEST_VERSION_HPP
+
+/*
+#include <srs_app_latest_version.hpp>
+*/
+
+#include <srs_core.hpp>
+
+#include <srs_app_thread.hpp>
+
+#include <string>
+
+class SrsLatestVersion : public ISrsEndlessThreadHandler
+{
+private:
+    SrsEndlessThread* trd_;
+    std::string server_id_;
+private:
+    std::string match_version_;
+    std::string stable_version_;
+public:
+    SrsLatestVersion();
+    virtual ~SrsLatestVersion();
+public:
+    virtual int start();
+// interface ISrsEndlessThreadHandler.
+public:
+    virtual int cycle();
+private:
+    int query_latest_version();
+};
+
+#endif
+
diff --git a/trunk/src/app/srs_app_server.cpp b/trunk/src/app/srs_app_server.cpp
index 9efdba41d..da180caeb 100755
--- a/trunk/src/app/srs_app_server.cpp
+++ b/trunk/src/app/srs_app_server.cpp
@@ -48,6 +48,7 @@ using namespace std;
 #include <srs_app_statistic.hpp>
 #include <srs_app_caster_flv.hpp>
 #include <srs_core_mem_watch.hpp>
+#include <srs_app_latest_version.hpp>
 
 // signal defines.
 #define SIGNAL_RELOAD SIGHUP
@@ -486,6 +487,7 @@ SrsServer::SrsServer()
     pid_fd = -1;
     
     signal_manager = NULL;
+    latest_version_ = new SrsLatestVersion();
     
     handler = NULL;
     ppid = ::getppid();
@@ -540,6 +542,7 @@ void SrsServer::destroy()
     }
     
     srs_freep(signal_manager);
+    srs_freep(latest_version_);
 }
 
 void SrsServer::dispose()
@@ -652,7 +655,18 @@ int SrsServer::initialize_st()
 
 int SrsServer::initialize_signal()
 {
-    return signal_manager->initialize();
+    int ret = ERROR_SUCCESS;
+
+    if ((ret = signal_manager->initialize()) != ERROR_SUCCESS) {
+        return ret;
+    }
+
+    // Start the version query coroutine.
+    if ((ret = latest_version_->start()) != ERROR_SUCCESS) {
+        return ret;
+    }
+
+    return ret;
 }
 
 int SrsServer::acquire_pid_file()
diff --git a/trunk/src/app/srs_app_server.hpp b/trunk/src/app/srs_app_server.hpp
index cd668d5e7..5f230e8aa 100644
--- a/trunk/src/app/srs_app_server.hpp
+++ b/trunk/src/app/srs_app_server.hpp
@@ -55,6 +55,7 @@ class SrsTcpListener;
 #ifdef SRS_AUTO_STREAM_CASTER
 class SrsAppCasterFlv;
 #endif
+class SrsLatestVersion;
 
 // listener type for server to identify the connection,
 // that is, use different type to process the connection.
@@ -267,6 +268,8 @@ private:
     * signal manager which convert gignal to io message.
     */
     SrsSignalManager* signal_manager;
+    // To query the latest available version of SRS.
+    SrsLatestVersion* latest_version_;
     /**
     * handle in server cycle.
     */
diff --git a/trunk/src/core/srs_core.hpp b/trunk/src/core/srs_core.hpp
index 84f48766f..9b39b5597 100644
--- a/trunk/src/core/srs_core.hpp
+++ b/trunk/src/core/srs_core.hpp
@@ -31,7 +31,7 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 // current release version
 #define VERSION_MAJOR       2
 #define VERSION_MINOR       0
-#define VERSION_REVISION    272
+#define VERSION_REVISION    274
 
 // generated by configure, only macros.
 #include <srs_auto_headers.hpp>
diff --git a/trunk/src/kernel/srs_kernel_utility.cpp b/trunk/src/kernel/srs_kernel_utility.cpp
index ba663604e..95b24a181 100644
--- a/trunk/src/kernel/srs_kernel_utility.cpp
+++ b/trunk/src/kernel/srs_kernel_utility.cpp
@@ -110,9 +110,17 @@ int64_t srs_get_system_startup_time_ms()
     if (_srs_system_time_startup_time <= 0) {
         srs_update_system_time_ms();
     }
-    
+
     return _srs_system_time_startup_time / 1000;
 }
+int64_t srs_get_system_startup_time_us()
+{
+    if (_srs_system_time_startup_time <= 0) {
+        srs_update_system_time_ms();
+    }
+
+    return _srs_system_time_startup_time;
+}
 int64_t srs_update_system_time_ms()
 {
     timeval now;
diff --git a/trunk/src/kernel/srs_kernel_utility.hpp b/trunk/src/kernel/srs_kernel_utility.hpp
index 085074848..de4023513 100644
--- a/trunk/src/kernel/srs_kernel_utility.hpp
+++ b/trunk/src/kernel/srs_kernel_utility.hpp
@@ -46,6 +46,7 @@ extern int srs_avc_nalu_read_bit(SrsBitStream* stream, int8_t& v);
 // get current system time in ms, use cache to avoid performance problem
 extern int64_t srs_get_system_time_ms();
 extern int64_t srs_get_system_startup_time_ms();
+extern int64_t srs_get_system_startup_time_us();
 // the deamon st-thread will update it.
 extern int64_t srs_update_system_time_ms();
 
diff --git a/trunk/src/protocol/srs_rtmp_handshake.cpp b/trunk/src/protocol/srs_rtmp_handshake.cpp
index c0c11bf0b..77f0dc1bc 100644
--- a/trunk/src/protocol/srs_rtmp_handshake.cpp
+++ b/trunk/src/protocol/srs_rtmp_handshake.cpp
@@ -484,7 +484,7 @@ namespace _srs_internal
     
     key_block::key_block()
     {
-        offset = (int32_t)rand();
+        offset = (int32_t)srs_random();
         random0 = NULL;
         random1 = NULL;
         
@@ -566,7 +566,7 @@ namespace _srs_internal
     
     digest_block::digest_block()
     {
-        offset = (int32_t)rand();
+        offset = (int32_t)srs_random();
         random0 = NULL;
         random1 = NULL;
         
diff --git a/trunk/src/protocol/srs_rtmp_utility.cpp b/trunk/src/protocol/srs_rtmp_utility.cpp
index 8c9b9908a..206253b8a 100644
--- a/trunk/src/protocol/srs_rtmp_utility.cpp
+++ b/trunk/src/protocol/srs_rtmp_utility.cpp
@@ -116,19 +116,25 @@ void srs_vhost_resolve(string& vhost, string& app, string& param)
 
 void srs_random_generate(char* bytes, int size)
 {
-    static bool _random_initialized = false;
-    if (!_random_initialized) {
-        srand(0);
-        _random_initialized = true;
-        srs_trace("srand initialized the random.");
-    }
-    
     for (int i = 0; i < size; i++) {
         // the common value in [0x0f, 0xf0]
-        bytes[i] = 0x0f + (rand() % (256 - 0x0f - 0x0f));
+        bytes[i] = 0x0f + (srs_random() % (256 - 0x0f - 0x0f));
     }
 }
 
+long srs_random()
+{
+    static bool _random_initialized = false;
+    if (!_random_initialized) {
+        _random_initialized = true;
+
+        srandom((unsigned int)srs_get_system_startup_time_us());
+        srs_trace("srandom initialized the random.");
+    }
+
+    return random();
+}
+
 string srs_generate_tc_url(string ip, string vhost, string app, string port, string param)
 {
     string tcUrl = "rtmp://";
diff --git a/trunk/src/protocol/srs_rtmp_utility.hpp b/trunk/src/protocol/srs_rtmp_utility.hpp
index 9344410c5..4a7211097 100644
--- a/trunk/src/protocol/srs_rtmp_utility.hpp
+++ b/trunk/src/protocol/srs_rtmp_utility.hpp
@@ -80,6 +80,8 @@ extern void srs_vhost_resolve(
 * generate ramdom data for handshake.
 */
 extern void srs_random_generate(char* bytes, int size);
+// Generate random value, use srandom(now_us) to init seed if not initialized.
+extern long srs_random();
 
 /**
 * generate the tcUrl.