diff --git a/fdroidserver/apksigcopier.py b/fdroidserver/apksigcopier.py
index 122f8302..adc3e507 100644
--- a/fdroidserver/apksigcopier.py
+++ b/fdroidserver/apksigcopier.py
@@ -99,6 +99,7 @@ class ReproducibleZipInfo(zipfile.ZipInfo):
     _override = {}  # type: Dict[str, Union[int, Tuple[int, ...]]]
 
     def __init__(self, zinfo, **override):
+        super().__init__()
         if override:
             self._override = {**self._override, **override}
         for k in self.__slots__:
diff --git a/fdroidserver/build.py b/fdroidserver/build.py
index ec697398..d7cf8ca5 100644
--- a/fdroidserver/build.py
+++ b/fdroidserver/build.py
@@ -48,6 +48,8 @@ try:
 except ImportError:
     pass
 
+buildserverid = None
+
 
 # Note that 'force' here also implies test mode.
 def build_server(app, build, vcs, build_dir, output_dir, log_dir, force):
@@ -951,7 +953,6 @@ def parse_commandline():
 
 options = None
 config = None
-buildserverid = None
 fdroidserverid = None
 start_timestamp = time.gmtime()
 status_output = None
diff --git a/fdroidserver/common.py b/fdroidserver/common.py
index c2394c06..a4679ff6 100644
--- a/fdroidserver/common.py
+++ b/fdroidserver/common.py
@@ -3257,6 +3257,7 @@ class ClonedZipInfo(zipfile.ZipInfo):
     """
 
     def __init__(self, zinfo):
+        super().__init__()
         self.original = zinfo
         for k in self.__slots__:
             try:
diff --git a/fdroidserver/exception.py b/fdroidserver/exception.py
index 7e6e32ab..097f4f68 100644
--- a/fdroidserver/exception.py
+++ b/fdroidserver/exception.py
@@ -1,5 +1,6 @@
 class FDroidException(Exception):
     def __init__(self, value=None, detail=None):
+        super().__init__()
         self.value = value
         self.detail = detail
 
@@ -23,6 +24,7 @@ class FDroidException(Exception):
 
 class MetaDataException(Exception):
     def __init__(self, value):
+        super().__init__()
         self.value = value
 
     def __str__(self):
diff --git a/fdroidserver/tail.py b/fdroidserver/tail.py
index d6e09691..8107f10d 100644
--- a/fdroidserver/tail.py
+++ b/fdroidserver/tail.py
@@ -105,6 +105,7 @@ class Tail(object):
 
 class TailError(Exception):
     def __init__(self, msg):
+        super().__init__()
         self.message = msg
 
     def __str__(self):
diff --git a/fdroidserver/update.py b/fdroidserver/update.py
index 83154ec8..4db8a2cc 100644
--- a/fdroidserver/update.py
+++ b/fdroidserver/update.py
@@ -2177,10 +2177,11 @@ def main():
     apks += files
     appid_has_apks = set()
     appid_has_repo_files = set()
+    remove_apks = []
     for apk in apks:
         to_remove = get_apks_without_allowed_signatures(apps.get(apk['packageName']), apk)
         if to_remove:
-            apks.remove(apk)
+            remove_apks.append(apk)
             logging.warning(
                 _('"{path}" is signed by a key that is not allowed:').format(
                     path=to_remove
@@ -2217,6 +2218,9 @@ def main():
                 else:
                     logging.warning(msg + '\n\t' + _('Use `fdroid update -c` to create it.'))
 
+    for apk in remove_apks:
+        apks.remove(apk)
+
     mismatch_errors = ''
     for appid in appid_has_apks:
         if appid in appid_has_repo_files: