25.12 to 26.3 Upgrade Errors and Fixes Attempted - iOS IMAP Broken

As promised, here's the data on the upgrade path I used and the errors and fixes;

Dropbox - Carbonio 26.3 Installation Logs

Currently running 25.12 on Ubuntu 22.04.5 (I did try a full dist-upgrade as well, without any difference).

Once iOS IMAP is broken, carbonio.log reveals nothing amiss (indeed it still recieves and sends mail from the webui without trouble) but the nginx error log fills with this (accounts redacted);

2026/03/16 17:50:40 [info] 5011#5011: *114 proxied session done, client: 172.16.8.69:56087, server: 0.0.0.0:993, login: "my@domain.net", upstream: 172.16.20.72:7143 (->172.16.20.72:993) <=> (172.16.20.72:51396->172.16.20.72:7143)
2026/03/16 17:50:40 [info] 5011#5011: *114 SSL_write() failed (SSL: error:80000020:system library::Broken pipe:tls_retry_write_records failure) (32: Broken pipe) while proxying, client: 172.16.8.69:56087, server: 0.0.0.0:993, login: "my@domain.net", upstream: 172.16.20.72:7143 (->172.16.20.72:993) <=> (->)
2026/03/16 17:50:40 [info] 5011#5011: *115 proxied session done, client: 172.16.8.69:56088, server: 0.0.0.0:993, login: "my@domain.net", upstream: 172.16.20.72:7143 (->172.16.20.72:993) <=> (172.16.20.72:51412->172.16.20.72:7143)
2026/03/16 17:50:40 [info] 5011#5011: *115 SSL_write() failed (SSL: error:80000020:system library::Broken pipe:tls_retry_write_records failure) (32: Broken pipe) while proxying, client: 172.16.8.69:56088, server: 0.0.0.0:993, login: "my@domain.net", upstream: 172.16.20.72:7143 (->172.16.20.72:993) <=> (->)
2026/03/16 17:50:40 [info] 5011#5011: *117 proxied session done, client: 172.16.8.69:56090, server: 0.0.0.0:993, login: "my@domain.net", upstream: 172.16.20.72:7143 (->172.16.20.72:993) <=> (172.16.20.72:51428->172.16.20.72:7143)
2026/03/16 17:50:40 [info] 5011#5011: *117 SSL_write() failed (SSL: error:80000020:system library::Broken pipe:tls_retry_write_records failure) (32: Broken pipe) while proxying, client: 172.16.8.69:56090, server: 0.0.0.0:993, login: "my@domain.net", upstream: 172.16.20.72:7143 (->172.16.20.72:993) <=> (->)
2026/03/16 17:50:40 [info] 5011#5011: *116 proxied session done, client: 172.16.8.69:56089, server: 0.0.0.0:993, login: "my@domain.net", upstream: 172.16.20.72:7143 (->172.16.20.72:993) <=> (172.16.20.72:51420->172.16.20.72:7143)
2026/03/16 17:50:40 [info] 5011#5011: *116 SSL_write() failed (SSL: error:80000020:system library::Broken pipe:tls_retry_write_records failure) (32: Broken pipe) while proxying, client: 172.16.8.69:56089, server: 0.0.0.0:993, login: "my@domain.net", upstream: 172.16.20.72:7143 (->172.16.20.72:993) <=> (->)
2026/03/16 17:50:40 [info] 5011#5011: *113 proxied session done, client: 172.16.8.69:56086, server: 0.0.0.0:993, login: "my@domain.net", upstream: 172.16.20.72:7143 (->172.16.20.72:993) <=> (172.16.20.72:51392->172.16.20.72:7143)
2026/03/16 17:50:40 [info] 5011#5011: *113 SSL_write() failed (SSL: error:80000020:system library::Broken pipe:tls_retry_write_records failure) (32: Broken pipe) while proxying, client: 172.16.8.69:56086, server: 0.0.0.0:993, login: "my@domain.net", upstream: 172.16.20.72:7143 (->172.16.20.72:993) <=> (->)
2026/03/16 17:50:41 [info] 5013#5013: *258 client 172.16.8.69:56114 connected to 0.0.0.0:993
2026/03/16 17:50:41 [info] 5013#5013: *259 client 172.16.8.69:56115 connected to 0.0.0.0:993
2026/03/16 17:50:41 [info] 5013#5013: *260 client 172.16.8.69:56116 connected to 0.0.0.0:993
2026/03/16 17:50:41 [info] 5013#5013: *261 client 172.16.8.69:56117 connected to 0.0.0.0:993
2026/03/16 17:50:41 [info] 5013#5013: *262 client 172.16.8.69:56118 connected to 0.0.0.0:993
2026/03/16 17:50:41 [info] 5013#5013: *258 client logged in, client: 172.16.8.69:56114, server: 0.0.0.0:993, login: "my@domain.net", upstream: 172.16.20.72:7143 (172.16.8.69:56114->172.16.20.72:993) <=> (172.16.20.72:52336->172.16.20.72:7143)
2026/03/16 17:50:41 [info] 5013#5013: *261 client logged in, client: 172.16.8.69:56117, server: 0.0.0.0:993, login: "my@domain.net", upstream: 172.16.20.72:7143 (172.16.8.69:56117->172.16.20.72:993) <=> (172.16.20.72:52362->172.16.20.72:7143)
2026/03/16 17:50:41 [info] 5013#5013: *262 client logged in, client: 172.16.8.69:56118, server: 0.0.0.0:993, login: "my@domain.net", upstream: 172.16.20.72:7143 (172.16.8.69:56118->172.16.20.72:993) <=> (172.16.20.72:52374->172.16.20.72:7143)
2026/03/16 17:50:41 [info] 5013#5013: *259 client logged in, client: 172.16.8.69:56115, server: 0.0.0.0:993, login: "my@domain.net", upstream: 172.16.20.72:7143 (172.16.8.69:56115->172.16.20.72:993) <=> (172.16.20.72:52348->172.16.20.72:7143)
2026/03/16 17:50:41 [info] 5013#5013: *260 client logged in, client: 172.16.8.69:56116, server: 0.0.0.0:993, login: "my@domain.net", upstream: 172.16.20.72:7143 (172.16.8.69:56116->172.16.20.72:993) <=> (172.16.20.72:52350->172.16.20.72:7143)
2026/03/16 17:50:42 [info] 5013#5013: *218 client timed out (110: Connection timed out) while SSL handshaking, client: 127.0.0.1, server: 0.0.0.0:443
2026/03/16 17:50:42 [notice] 5011#5011: memcached channel:127.78.0.1:20014 orderly shutdown
2026/03/16 17:50:42 [notice] 5011#5011: memcached channel:127.78.0.1:20014 down, reconnect after:60000 ms
2026/03/16 17:50:42 [info] 5013#5013: *219 client timed out (110: Connection timed out) while SSL handshaking, client: 127.0.0.1, server: 0.0.0.0:443
2026/03/16 17:50:42 [notice] 5012#5012: memcached channel:127.78.0.1:20014 orderly shutdown
2026/03/16 17:50:42 [notice] 5012#5012: memcached channel:127.78.0.1:20014 down, reconnect after:60000 ms
2026/03/16 17:50:42 [info] 5013#5013: *223 client timed out (110: Connection timed out) while SSL handshaking, client: 127.0.0.1, server: 0.0.0.0:443
2026/03/16 17:50:42 [notice] 5014#5014: memcached channel:127.78.0.1:20014 orderly shutdown
2026/03/16 17:50:42 [notice] 5014#5014: memcached channel:127.78.0.1:20014 down, reconnect after:60000 ms
2026/03/16 17:50:43 [info] 5013#5013: *268 client closed connection while SSL handshaking, client: 127.0.0.1, server: 0.0.0.0:443
2026/03/16 17:50:47 [info] 5014#5014: *270 client closed connection while SSL handshaking, client: 127.0.0.1, server: 0.0.0.0:443
2026/03/16 17:50:48 [info] 5014#5014: *271 client closed connection while SSL handshaking, client: 127.0.0.1, server: 0.0.0.0:443
2026/03/16 17:50:53 [info] 5014#5014: *273 client closed connection while SSL handshaking, client: 127.0.0.1, server: 0.0.0.0:443
2026/03/16 17:50:57 [info] 5014#5014: *275 client closed connection while SSL handshaking, client: 127.0.0.1, server: 0.0.0.0:443
2026/03/16 17:50:58 [info] 5014#5014: *276 client closed connection while SSL handshaking, client: 127.0.0.1, server: 0.0.0.0:443
2026/03/16 17:51:03 [info] 5014#5014: *278 client closed connection while SSL handshaking, client: 127.0.0.1, server: 0.0.0.0:443