diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index f5d94dc49..2bf54cd58 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -20,7 +20,7 @@ jobs:
     - name: Set up Python
       uses: actions/setup-python@v2
       with:
-          python-version: '3.x'
+          python-version: '3.8'
     - name: Install packages
       run: sudo apt-get -y install zip pandoc man
     - name: Bump version
diff --git a/youtube_dlc/downloader/common.py b/youtube_dlc/downloader/common.py
index 8803c5a95..ce8d8b8f8 100644
--- a/youtube_dlc/downloader/common.py
+++ b/youtube_dlc/downloader/common.py
@@ -365,11 +365,12 @@ class FileDownloader(object):
                         else '%.2f' % sleep_interval))
                 time.sleep(sleep_interval)
         else:
-            sleep_interval_sub = self.params.get('sleep_interval_subtitles')
-            self.to_screen(
-                '[download] Sleeping %s seconds...' % (
-                    int(sleep_interval_sub)))
-            time.sleep(sleep_interval_sub)
+            if self.params.get('sleep_interval_subtitles') > 0:
+                sleep_interval_sub = self.params.get('sleep_interval_subtitles')
+                self.to_screen(
+                    '[download] Sleeping %s seconds...' % (
+                        sleep_interval_sub))
+                time.sleep(sleep_interval_sub)
 
         if info_dict.get('heartbeat'):
             self.heartbeat = Heartbeat(self.ydl, info_dict.get('heartbeat'))
diff --git a/youtube_dlc/extractor/viki.py b/youtube_dlc/extractor/viki.py
index f8e360338..0f188f84d 100644
--- a/youtube_dlc/extractor/viki.py
+++ b/youtube_dlc/extractor/viki.py
@@ -308,19 +308,17 @@ class VikiIE(VikiBaseIE):
                 'url': thumbnail.get('url'),
             })
 
-        stream_ids = []
-        for f in formats:
-            s_id = f.get('stream_id')
-            if s_id is not None:
-                stream_ids.append(s_id)
+        new_video = self._download_json(
+            'https://www.viki.com/api/videos/%s' % video_id, video_id,
+            'Downloading new video JSON to get subtitles', headers={'x-viki-app-ver': '2.2.5.1428709186'}, expected_status=[200, 400, 404])
 
         subtitles = {}
-        for subtitle_lang, _ in video.get('subtitle_completions', {}).items():
-            subtitles[subtitle_lang] = [{
-                'ext': subtitles_format,
-                'url': self._prepare_call(
-                    'videos/%s/subtitles/%s.%s?stream_id=%s' % (video_id, subtitle_lang, subtitles_format, stream_ids[0])),
-            } for subtitles_format in ('srt', 'vtt')]
+        for sub in new_video.get('streamSubtitles').get('dash'):
+            subtitles[sub.get('srclang')] = [{
+                'ext': 'vtt',
+                'url': sub.get('src'),
+                'completion': sub.get('percentage'),
+            }]
 
         result = {
             'id': video_id,
diff --git a/youtube_dlc/options.py b/youtube_dlc/options.py
index 66b45220c..3c8a1305e 100644
--- a/youtube_dlc/options.py
+++ b/youtube_dlc/options.py
@@ -582,7 +582,7 @@ def parseOpts(overrideArguments=None):
             'along with --min-sleep-interval.'))
     workarounds.add_option(
         '--sleep-subtitles',
-        dest='sleep_interval_subtitles', action='store_true', default=0,
+        dest='sleep_interval_subtitles', default=0, type=int,
         help='Enforce sleep interval on subtitles as well')
 
     verbosity = optparse.OptionGroup(parser, 'Verbosity / Simulation Options')