Update from 0.20

I’ve been running v0.20 from 2016 & when the daily_tasks.py runs there are errors and the system hangs.
This can be replicated by running the backup.py

ERROR when running backup.py
~/mailinabox# ./management/backup.py
Traceback (most recent call last):
File “/usr/bin/duplicity”, line 1494, in
File “/usr/bin/duplicity”, line 1488, in with_tempdir
File “/usr/bin/duplicity”, line 1337, in main
File “/usr/bin/duplicity”, line 1470, in do_backup
File “/usr/bin/duplicity”, line 637, in incremental_backup
File “/usr/bin/duplicity”, line 403, in write_multivol
globals.gpg_profile, globals.volsize)
File “/usr/lib/python2.7/dist-packages/duplicity/gpg.py”, line 331, in GPGWriteFile
data = block_iter.next().data
File “/usr/lib/python2.7/dist-packages/duplicity/diffdir.py”, line 518, in next
result = self.process(self.input_iter.next())
File “/usr/lib/python2.7/dist-packages/duplicity/diffdir.py”, line 190, in get_delta_iter
for new_path, sig_path in collated:
File “/usr/lib/python2.7/dist-packages/duplicity/diffdir.py”, line 281, in collate2iters
relem2 = riter2.next()
File “/usr/lib/python2.7/dist-packages/duplicity/diffdir.py”, line 346, in combine_path_iters
File “/usr/lib/python2.7/dist-packages/duplicity/diffdir.py”, line 322, in get_triple
path = path_iter_list[iter_index].next()
File “/usr/lib/python2.7/dist-packages/duplicity/diffdir.py”, line 232, in sigtar2path_iter
tf = util.make_tarfile(“r”, sigtarobj)
File “/usr/lib/python2.7/dist-packages/duplicity/util.py”, line 113, in make_tarfile
tf = tarfile.TarFile(“arbitrary”, mode, fp)
File “/usr/lib/python2.7/dist-packages/duplicity/tarfile.py”, line 1573, in init
self.firstmember = self.next()
File “/usr/lib/python2.7/dist-packages/duplicity/tarfile.py”, line 2323, in next
tarinfo = self.tarinfo.fromtarfile(self)
File “/usr/lib/python2.7/dist-packages/duplicity/tarfile.py”, line 1235, in fromtarfile
buf = tarfile.fileobj.read(BLOCKSIZE)
File “/usr/lib/python2.7/gzip.py”, line 261, in read
File “/usr/lib/python2.7/gzip.py”, line 296, in _read
File “/usr/lib/python2.7/gzip.py”, line 190, in _read_gzip_header
raise IOError, 'Not a gzipped file’
IOError: Not a gzipped file

^CTraceback (most recent call last):
File “./management/backup.py”, line 514, in
File “./management/backup.py”, line 287, in perform_backup
File “/home/USER/mailinabox/management/utils.py”, line 193, in shell
ret = getattr(subprocess, method)(cmd_args, **kwargs)
File “/usr/lib/python3.4/subprocess.py”, line 556, in check_call
retcode = call(*popenargs, **kwargs)
File “/usr/lib/python3.4/subprocess.py”, line 539, in call
return p.wait(timeout=timeout)
File “/usr/lib/python3.4/subprocess.py”, line 1566, in wait
(pid, sts) = self._try_wait(0)
File “/usr/lib/python3.4/subprocess.py”, line 1514, in _try_wait
(pid, sts) = _eintr_retry_call(os.waitpid, self.pid, wait_flags)
File “/usr/lib/python3.4/subprocess.py”, line 491, in _eintr_retry_call
return func(*args)

I get the error below when trying to update, have done apt-get update + apt-get distupgrade & no change.

curl -s https://mailinabox.email/setup.sh | sudo bash

Updating Mail-in-a-Box to v0.24 . . .
git-remote-https: error while loading shared libraries: /usr/lib/x86_64-linux-gnu/libcurl-gnutls.so.4: invalid ELF header
error: pathspec ‘v0.24’ did not match any file(s) known to git.
Update failed. Did you modify something in /home/USER/mailinabox?

Please advise.

Is it possible to get a version by version upgrade - so from 0.20 to 0.21 and so on?
This might fix the bug I have with upgrading from 0.20 to 0.24
Clean system 0.24 install works perfectly … please help.