Sudden warning and error in PHP 7.0 and 7.1 NOT 5.6

Hi

I have a site running Runway and Shop and am suddenly experiencing a sudden error / failure in PHP 7.0. I've switched back to 5.6 and all is fine for now. I understand this might be a hosting issue but wanted to flag the issue here in case it's part of the core Shop code becoming outdated.

No code on my site has changed on the site in months and it's made a couple of hundred transactions without failure since last year.

On basket pages I see this error:

Warning: Unknown: using touch command with binary protocol is not recommended with libmemcached versions below 1.0.18, please use ascii protocol or upgrade libmemcached in Unknown on line 0

When checking out there's suddenly a blank page and the following warnings:

Warning: session_write_close(): using touch command with binary protocol is not recommended with libmemcached versions below 1.0.18, please use ascii protocol or upgrade libmemcached in /var/sites/e/ellipress.co.uk/public_html/perch/core/lib/PerchSession.class.php on line 88

Warning: Cannot modify header information - headers already sent by (output started at /var/sites/e/ellipress.co.uk/public_html/perch/core/lib/PerchSession.class.php:88) in /var/sites/e/ellipress.co.uk/public_html/perch/core/lib/PerchUtil.class.php on line 233

I've logged this with the host (TSO) and am waiting to hear back.

Full diagnostics:

Perch Runway: 3.1.2
Production mode: Production (100)
Installed apps: content (3.1.2), assets (3.1.2), categories (3.1.2), perch_forms (1.12), perch_shop_orders (1.2.6), perch_shop_products (1.2.6), perch_shop (1.2.6), perch_members (1.6.4), pipit_catalog (1.2.0), perch_mailchimp (3.1)
DB driver: PDO
DB tables: perch3_backup_plans (1), perch3_backup_resources (1269), perch3_backup_runs (502), perch3_categories (6), perch3_category_counts (0), perch3_category_sets (2), perch3_collection_index (0), perch3_collection_items (0), perch3_collection_revisions (0), perch3_collections (0), perch3_content_index (489), perch3_content_items (128), perch3_content_locks (1), perch3_content_regions (34), perch3_forms (1), perch3_forms_responses (72), perch3_mailchimp_campaigns (4), perch3_mailchimp_imports (0), perch3_mailchimp_lists (4), perch3_mailchimp_subscribers (27), perch3_mailchimp_subscriptions (28), perch3_mailchimp_webhooks (3), perch3_members (290), perch3_members_forms (1), perch3_members_member_tags (0), perch3_members_sessions (2), perch3_members_tags (0), perch3_menu_items (17), perch3_navigation (3), perch3_navigation_pages (11), perch3_page_routes (8), perch3_page_templates (31), perch3_pages (30), perch3_resource_log (1063), perch3_resource_tags (1), perch3_resources (1271), perch3_resources_to_tags (1), perch3_scheduled_tasks (22), perch3_settings (62), perch3_shop_addresses (783), perch3_shop_admin_index (192), perch3_shop_brands (6), perch3_shop_cart (66345), perch3_shop_cart_data (1492), perch3_shop_cart_items (1147), perch3_shop_countries (250), perch3_shop_currencies (152), perch3_shop_customers (302), perch3_shop_emails (2), perch3_shop_index (16230), perch3_shop_option_values (26), perch3_shop_options (2), perch3_shop_order_items (874), perch3_shop_order_promotions (79), perch3_shop_order_statuses (9), perch3_shop_orders (358), perch3_shop_orders_meta (1), perch3_shop_product_files (0), perch3_shop_product_option_values (121), perch3_shop_product_options (46), perch3_shop_product_tags (0), perch3_shop_products (217), perch3_shop_promotions (9), perch3_shop_sales (3), perch3_shop_search (209), perch3_shop_shipping_zone_countries (92), perch3_shop_shipping_zones (4), perch3_shop_shippings (6), perch3_shop_tax_exhibits (1237), perch3_shop_tax_group_rates (37), perch3_shop_tax_groups (2), perch3_shop_tax_locations (36), perch3_shop_tax_rates (38), perch3_shop_variants (170), perch3_user_passwords (0), perch3_user_privileges (77), perch3_user_role_buckets (4), perch3_user_role_privileges (4), perch3_user_roles (2), perch3_users (3)
Users: 3
App runtimes:
<?php
    $apps_list = [ 
        'perch_mailchimp',
        'perch_members',
        'perch_shop',
        'perch_forms',
    ];
Scheduled tasks for perch_mailchimp: import_data (1 mins)
Scheduled tasks for Backup: plan_1 (10 mins)
Editor plug-ins:
H1: 055f3c6d3413d97ba28b5052e9a7cff5
L1: 408bb23a517077bcb1b9fc47ccd6a29e
F1: 3b606135b33e6a102526838f4152a807
headerColour: #000000
content_singlePageEdit: 1
helpURL:
siteURL: https://ellipress.co.uk
hideBranding: 0
content_collapseList: 1
lang: en-gb
installedAt: 3.0b16
update_3.0b16: done
headerScheme: dark
update_runway_3.0b16: done
latest_version:
on_sale_version:
perch_shop_update: 1.2.6
perch_mailchimp_api_key: 9bafedadf845786999b8259230c631ea-us6
perch_mailchimp_campaign_url: /mailchimp/campaign/{campaignSlug}
perch_members_login_page: /members/login.php?r={returnURL}
perch_shop_price_tax_mode: inc
perch_shop_trade_price_tax_mode: exc
perch_shop_product_url: /shop/products/{slug}
perch_shop_default_currency: 47
perch_shop_reporting_currency: 47
perch_shop_invoice_number_format: EP%d
dashboard: 0
hide_pwd_reset: 0
siteOffline: 0
content_hideNonEditableRegions: 0
content_frontend_edit: 0
perch_mailchimp_secret: 3cd38bc
update_runway_3.0.1: done
perch_members_update: 1.4
update_runway_3.0.2: done
update_runway_3.0.5: done
update_runway_3.0.6: done
update_runway_3.0.7: done
update_runway_3.0.8: done
keyboardShortcuts: 0
content_skip_region_list: 0
update_runway_3.0.9: done
assets_restrict_buckets: 0
perch_shop_site_url: https://ellipress.co.uk
update_runway_3.0.10: done
update_runway_3.0.11: done
sidebar_back_link: 0
pipit_catalog_productsSet:
pipit_catalog_lowStok:
pipit_catalog_thumbW:
pipit_catalog_thumbH:
pipit_catalog_thumbDensity:
pipit_catalog_hideCat: 0
pipit_catalog_hideBrand: 0
pipit_catalog_hideStatus: 0
pipit_catalog_hideSale: 0
pipit_catalog_hideShipping: 0
pipit_catalog_hideSearch: 0
pipit_catalog_hideProductImages: 0
pipit_catalog_displaySalePrices: 0
pipit_catalog_thumbCrop: 0
logoPath: /perch/resources/ep-animated-logo.gif
update_runway_3.0.14: done
update_runway_3.1.1: done
update_runway_3.1.2: done
PERCH_DEVELOPMENT: 10
PERCH_STAGING: 50
PERCH_PRODUCTION: 100
PERCH_DB_USERNAME: ellipres_perchrw
PERCH_DB_SERVER: 10.169.0.152
PERCH_DB_DATABASE: ellipres_perchrw
PERCH_DB_PREFIX: perch3_
PERCH_SITEPATH: /var/sites/e/ellipress.co.uk/public_html
PERCH_EMAIL_METHOD: smtp
PERCH_EMAIL_HOST: 10.168.1.70
PERCH_EMAIL_PORT: 25
PERCH_TZ: Europe/London
PERCH_EMAIL_FROM: hello@ellipress.co.uk
PERCH_EMAIL_FROM_NAME: Ellipress
PERCH_LOGINPATH: /perch
PERCH_PATH: /var/sites/e/ellipress.co.uk/public_html/perch
PERCH_CORE: /var/sites/e/ellipress.co.uk/public_html/perch/core
PERCH_RESFILEPATH: /var/sites/e/ellipress.co.uk/public_html/perch/resources
PERCH_RESPATH: /perch/resources
PERCH_HTML5: 1
PERCH_SCHEDULE_SECRET: FyHIGLV2WB9HEwKD
PERCH_RUNWAY: 1
PERCH_ERROR_MODE: DIE
PERCH_DATE_LONG: %d %B %Y
PERCH_DATE_SHORT: %d %b %Y
PERCH_TIME_SHORT: %H:%M
PERCH_TIME_LONG: %H:%M:%S
PERCH_RUNWAY_ROUTED:
PERCH_STRONG_PASSWORDS:
PERCH_ASSET_VERSION: 6738d5d5f5664f7c5e34
PERCH_DEBUG:
PERCH_PREVIEW_ARG: preview
PERCH_TEMPLATE_PATH: /var/sites/e/ellipress.co.uk/public_html/perch/templates
PERCH_TEMPLATE_FILTERS:
PERCH_DEFAULT_DOC: index.php
PERCH_DEFAULT_EXT: .php
PERCH_PRODUCTION_MODE: 100
PERCH_XHTML_MARKUP:
PERCH_RWD: 1
PERCH_HTML_ENTITIES:
PERCH_SSL:
PERCH_STRIPSLASHES:
PERCH_PROGRESSIVE_FLUSH: 1
PERCH_PARANOID:
PERCH_FORCE_SECURE_COOKIES:
PERCH_DEFAULT_BUCKET: default
PERCH_TRANSLATION_ASSIST:
PERCH_PASSWORD_MIN_LENGTH: 6
PERCH_MAX_FAILED_LOGINS: 10
PERCH_AUTH_LOCKOUT_DURATION: 1 HOUR
PERCH_VERIFY_UPLOADS:
PERCH_PRIV_ASSIST:
PERCH_CUSTOM_EDITOR_CONFIGS:
PERCH_ENABLE_EXIF: 1
PERCH_AUTH_PLUGIN:
PERCH_DB_CHARSET: utf8
PERCH_DB_PORT:
PERCH_DB_SOCKET:
PERCH_SHOP_VERSION: 1.2.6
PERCH_APPS_EDITOR_PLUGIN: markitup
PERCH_APPS_EDITOR_MARKUP_LANGUAGE: markdown
Hosting settings

PHP: 5.6.37
Zend: 2.6.0
OS: Linux
SAPI: cgi-fcgi
Safe mode: not detected
MySQL client: mysqlnd 5.0.11-dev - 20120503 - $Id: 76b08b24596e12d4553bd41fc93cccd5bac2fe7a $
MySQL server: 5.7.17
Free disk space: 38.39 TB
Extensions: Core, date, ereg, libxml, openssl, pcre, sqlite3, zlib, bcmath, bz2, calendar, ctype, curl, dba, dom, hash, fileinfo, filter, ftp, gettext, gmp, SPL, iconv, session, intl, json, mbstring, mcrypt, mssql, standard, mysqlnd, pcntl, mysqli, PDO, pdo_mysql, pdo_pgsql, pdo_sqlite, pgsql, Phar, posix, readline, Reflection, imap, shmop, SimpleXML, snmp, soap, sockets, exif, sysvshm, tidy, tokenizer, wddx, xml, xmlreader, xmlrpc, xmlwriter, xsl, zip, cgi-fcgi, memcached, memcache, geoip, imagick, mysql, gd, ldap, mhash, ionCube Loader, Zend Guard Loader
GD: Yes
ImageMagick: Yes
PHP max upload size: 100M
PHP max form post size: 100M
PHP memory limit: 128M
Total max uploadable file size: 100M
Resource folder writeable: Yes
Session timeout: 240 minutes
Native JSON: Yes
Filter functions: Yes
Transliteration functions: Yes
DOCUMENT_ROOT: /var/sites/e/ellipress.co.uk/public_html
GATEWAY_INTERFACE: CGI/1.1
HTTPS: On
HTTP_ACCEPT: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
HTTP_ACCEPT_ENCODING: br, gzip, deflate
HTTP_ACCEPT_LANGUAGE: en-gb
HTTP_CONNECTION: close
HTTP_COOKIE: _ga=GA1.3.1718981156.1540568583; _gid=GA1.3.447942994.1540656163; PHPSESSID=f6e090ef77a5363e0df3399dac0a34e2; _gat_gtag_UA_9873373_4=1; cmsa=1; p_m=; MCPopupClosed=yes
HTTP_HOST: ellipress.co.uk
HTTP_REFERER: https://ellipress.co.uk/perch/core/settings/diagnostics/
HTTP_USER_AGENT: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/12.0 Safari/605.1.15
HTTP_X_FORWARDED_FOR: 86.152.67.52
HTTP_X_FORWARDED_PROTO: https
HTTP_X_HTTPS: On
HTTP_X_PORT: 443
PATH: /bin
QUERY_STRING: extended
REDIRECT_STATUS: 200
REMOTE_ADDR: 86.152.67.52
REMOTE_PORT: 35193
REQUEST_METHOD: GET
REQUEST_URI: /perch/core/settings/diagnostics/?extended
SCRIPT_FILENAME: /var/sites/e/ellipress.co.uk/public_html/perch/core/settings/diagnostics/index.php
SCRIPT_NAME: /perch/core/settings/diagnostics/index.php
SERVER_ADDR: 10.170.0.58
SERVER_ADMIN: webmaster@gridhost.co.uk
SERVER_NAME: ellipress.co.uk
SERVER_PORT: 443
SERVER_PROTOCOL: HTTP/1.1
SERVER_SOFTWARE: Apache
UNIQUE_ID: W9STiQqqADoAAAnNnisAAABq
PHP_SELF: /perch/core/settings/diagnostics/index.php
REQUEST_TIME_FLOAT: 1540658058.01
REQUEST_TIME: 1540658058
argc: 1