The front end and back end both appear to work perfectly. Before upgrade I go to the module manager. I see lots of "Missing dependencies" & "This module is awaiting upgrade."
Still in the module manager I click Upgrade on a couple of modules and I see error "The CMSMS core must be upgraded before this operation can succeed. A problem occurred communicating with the module server."
I run an upgrade anyway. It appears to go smoothly but after the upgrade I get php 500 errors in both the front end and back end:
PHP Fatal error: Allowed memory size of 805306368 bytes exhausted
Would be grateful for any pointers as to how to successfully upgrade this site.
Thanks!

EDIT: I copied the system to another host and tried there but I get the same behaviour, so it's not the host which is the problem.
Original state:
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Cms Version: 2.2.9
Installed Modules:
AdminSearch: 1.0.2
CGContentUtils: 2.1.5
CGExtensions: 1.53.13
CGHeadMaster: 1.0.9.2
CGSimpleSmarty: 2.1.4
CMSContentManager: 1.1.4
CmsJobManager: 0.1.2
DesignManager: 1.1.1
FileManager: 1.5.2
FilePicker: 1.0.2
Gallery: 2.1.6
JQueryTools: 1.3.9
MenuManager: 1.50.2
MicroTiny: 2.0.3
ModuleManager: 2.0.5
Navigator: 1.0.3
News: 2.50.6
Search: 1.50.2
Config Information:
php_memory_limit:
max_upload_size: 128000000
url_rewriting: mod_rewrite
page_extension: /
query_var: page
auto_alias_content: true
locale:
set_names: true
timezone: Europe/London
permissive_smarty: true
Php Information:
phpversion: 5.6.40
md5_function: On (True)
json_function: On (True)
gd_version: 2
tempnam_function: On (True)
magic_quotes_runtime: Off (False)
E_ALL: 32759
E_STRICT: 2048
E_DEPRECATED: 8192
test_file_timedifference: No time difference found
test_db_timedifference: No time difference found
create_dir_and_file: 1
memory_limit: 768M
max_execution_time: 300
register_globals: Off (False)
output_buffering: 4096
disable_functions:
open_basedir:
test_remote_url: Success
file_uploads: On (True)
post_max_size: 128M
upload_max_filesize: 128M
session_save_path: /tmp (0700)
session_use_cookies: On (True)
xml_function: On (True)
xmlreader_class: On (True)
check_ini_set: On (True)
curl: On
Performance Information:
allow_browser_cache: Off (False)
browser_cache_expiry: 60
php_opcache: On (True)
smarty_cache: Off (False)
smarty_compilecheck: Off (False)
auto_clear_cache_age: On (True)
Server Information:
Server Software: LiteSpeed
Server Api: litespeed
Server Os: Linux 2.6.32-954.3.5.lve1.4.59.el6.x86_64 On x86_64
Server Db Type: MySQL (mysqli)
Server Db Version: 10.1.40
Server Db Grants: Found a "GRANT ALL" statement that appears to be suitable
Permission Information:
tmp: /home/patinaar/public_html/tmp (0755)
tmp_cache: /home/patinaar/public_html/tmp/cache (0755)
templates_c: /home/patinaar/public_html/tmp/templates_c (0755)
modules: /home/patinaar/public_html/modules (0755)
uploads: /home/patinaar/public_html/uploads (0755)
File Creation Mask (umask): /home/patinaar/public_html/tmp/cache (0755)
config_file: 0644
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