diff --git a/bin/weewx/drivers/ws28xx.py b/bin/weewx/drivers/ws28xx.py
index ffc6818a..cda6ad86 100644
--- a/bin/weewx/drivers/ws28xx.py
+++ b/bin/weewx/drivers/ws28xx.py
@@ -4081,7 +4081,7 @@ class CCommunicationService(object):
         self.running = False
         log.debug('stopRFThread: waiting for RF thread to terminate')
         self.child.join(self.thread_wait)
-        if self.child.isAlive():
+        if self.child.is_alive():
             log.error('unable to terminate RF thread after %d seconds'
                       % self.thread_wait)
         else:
diff --git a/bin/weewx/engine.py b/bin/weewx/engine.py
index cbf2f1bc..c874877e 100644
--- a/bin/weewx/engine.py
+++ b/bin/weewx/engine.py
@@ -792,7 +792,7 @@ class StdReport(StdService):
         # Do not launch the reporting thread if an old one is still alive.
         # To guard against a zombie thread (alive, but doing nothing) launch
         # anyway if enough time has passed.
-        if self.thread and self.thread.isAlive():
+        if self.thread and self.thread.is_alive():
             thread_age = time.time() - self.launch_time
             if thread_age < self.max_wait:
                 log.info("Launch of report thread aborted: existing report thread still running")
@@ -816,7 +816,7 @@ class StdReport(StdService):
         if self.thread:
             log.info("Shutting down StdReport thread")
             self.thread.join(20.0)
-            if self.thread.isAlive():
+            if self.thread.is_alive():
                 log.error("Unable to shut down StdReport thread")
             else:
                 log.debug("StdReport thread has been terminated")
diff --git a/bin/weewx/restx.py b/bin/weewx/restx.py
index 2d582d3f..15487cde 100644
--- a/bin/weewx/restx.py
+++ b/bin/weewx/restx.py
@@ -148,12 +148,12 @@ class StdRESTful(weewx.engine.StdService):
     @staticmethod
     def shutDown_thread(q, t):
         """Function to shut down a thread."""
-        if q and t.isAlive():
+        if q and t.is_alive():
             # Put a None in the queue to signal the thread to shutdown
             q.put(None)
             # Wait up to 20 seconds for the thread to exit:
             t.join(20.0)
-            if t.isAlive():
+            if t.is_alive():
                 log.error("Unable to shut down %s thread", t.name)
             else:
                 log.debug("Shut down %s thread.", t.name)