OnlyOffice 9.2.1 on Debian after Upgrade from OF 7.0.1-37 JSON doesn't work

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Document Server version: 9.2.1-8
Type of installation of the Document Server (docker, deb/rpm, exe, please point us to the installation guide that you used as well): Deb/RPM Installation Guide
OS: Debian 11
Browser version: Google Chrome Version 144.0.7559.97 (Official Build) (arm64)
Additional information:
Any relevant details about the situation. This is an old installation of OnlyOffice 7.0.1-37 which has been upgraded to 9.2.1-8 but after the upgradation the system has stopped working as expected also this system has an integration with a PHP application (aka SugarCRM).

  1. error in out.log file is as follow
    SyntaxError: Unexpected end of JSON input
    at JSON.parse ()
    at Object. (/snapshot/server/Common/sources/logger.js)
    at Module._compile (pkg/prelude/bootstrap.js:1925:22)
    at Module._extensions…js (node:internal/modules/cjs/loader:1623:10)
    at Module.load (node:internal/modules/cjs/loader:1266:32)
    at Module._load (node:internal/modules/cjs/loader:1091:12)
    at Module.require (node:internal/modules/cjs/loader:1289:19)
    at Module.require (pkg/prelude/bootstrap.js:1846:31)
    at require (node:internal/modules/helpers:182:18)
    at Object. (/snapshot/server/DocService/sources/server.js)

  2. DS docservice is in a reboot state. It doesn’t become active
    ● ds-docservice.service - Docs Docservice
    Loaded: loaded (/usr/lib/systemd/system/ds-docservice.service; enabled; vendor preset: enabled)
    Active: activating (auto-restart) since Mon 2026-01-26 05:29:42 PST; 9s ago
    Process: 31888 ExecStart=/bin/sh -c exec /var/www/onlyoffice/documentserver/server/DocService/docservice 2>&1 | tee -a /var/log/onlyoffice/documentserver/docservice/out.log (code=exited, status=0/SUCCESS)
    Main PID: 31888 (code=exited, status=0/SUCCESS)
    CPU: 430ms

  3. In browser integration is displaying wss error.

Hello @DrunkDeveloper

Did you choose the option to preserve the configs during the update? Usually, such errors appear due to incorrect configs. The leap in between the versions is significant, many new items were added to the configs, thus preserving old ones could have caused this issue.

If you did preserve old configs, I recommend uninstalling Document Server and running a clean install.