diff --git a/management/backup.py b/management/backup.py
index f5773ca..8b5b050 100755
--- a/management/backup.py
+++ b/management/backup.py
@@ -12,7 +12,7 @@ import dateutil.parser, dateutil.relativedelta, dateutil.tz
 import rtyaml
 from exclusiveprocess import Lock, CannotAcquireLock
 
-from utils import load_environment, shell, wait_for_service, fix_boto, get_php_version
+from utils import load_environment, shell, wait_for_service, fix_boto, get_php_version, get_os_code
 
 rsync_ssh_options = [
 	"--ssh-options= -i /root/.ssh/id_rsa_miab",
@@ -471,8 +471,20 @@ def list_target_files(config):
 
 		return [(key.name[len(path):], key.size) for key in bucket.list(prefix=path)]
 	elif target.scheme == 'b2':
-		from b2sdk.v1 import InMemoryAccountInfo, B2Api
-		from b2sdk.v1.exception import NonExistentBucket
+		InMemoryAccountInfo = None
+		B2Api = None
+		NonExistentBucket = None
+
+		if get_os_code() == "Debian10":
+			# WARNING: This is deprecated code using a legacy library.
+			# We need it because Debian 10 ships with an old version of Duplicity
+			from b2.account_info import InMemoryAccountInfo
+			from b2.api import B2Api
+			from b2.exception import NonExistentBucket
+		else:
+			from b2sdk import InMemoryAccountInfo, B2Api
+			from b2sdk import NonExistentBucket
+
 		info = InMemoryAccountInfo()
 		b2_api = B2Api(info)
 		
diff --git a/setup/management.sh b/setup/management.sh
index 7927574..2600a16 100755
--- a/setup/management.sh
+++ b/setup/management.sh
@@ -27,10 +27,9 @@ done
 # provision free TLS certificates.
 apt_install duplicity python3-pip python3-gpg virtualenv certbot
 
-# b2sdk is used for backblaze backups.
 # boto is used for amazon aws backups.
 # Both are installed outside the pipenv, so they can be used by duplicity
-hide_output pip3 install --upgrade b2sdk boto
+hide_output pip3 install --upgrade boto
 
 # Create a virtualenv for the installation of Python 3 packages
 # used by the management daemon.
@@ -51,7 +50,23 @@ hide_output $venv/bin/pip install --upgrade \
 	rtyaml "email_validator>=1.0.0" "exclusiveprocess" \
 	flask dnspython python-dateutil \
   qrcode[pil] pyotp \
-	"idna>=2.0.0" "cryptography==2.2.2" boto psutil postfix-mta-sts-resolver b2sdk
+	"idna>=2.0.0" "cryptography==2.2.2" boto psutil postfix-mta-sts-resolver
+
+# Install backblaze B2 libraries.
+# Depending on the OS, Duplicity may require different dependencies.
+case $(get_os_code) in
+
+	$OS_DEBIAN_10)
+		hide_output pip3 install --upgrade "b2<2.0.0"
+		hide_output $venv/bin/pip install --upgrade "b2<2.0.0"
+		;;
+	
+	$OS_UBUNTU_2004)
+		hide_output pip3 install --upgrade "b2sdk==1.7.0"
+		hide_output $venv/bin/pip install --upgrade "b2sdk==1.7.0"
+		;;
+
+esac
 
 # Make the venv use the packaged gpgme bindings (the ones pip provides are severely out-of-date)
 if [ ! -d $venv/lib/python$(python_version)/site-packages/gpg/ ]; then