Bugs encoding Russian Cyrillic letters when downloading zip files through the web interface, owncloud 9.1. The description of fixes encoding problems
Облако 9.1 версии, краказяблы при скачивании. Описание устранения проблемы.

to correct the problem with the coding we need to make changes to the file
/ var / www / owncloud / lib / private / Streamer.php
Line 66
Original: $this->streamerInstance->addEmptyDir($rootDir);
Change: $this->streamerInstance->addEmptyDir(iconv("utf-8", "cp866", $rootDir));
Line 69
Original: $this->addFileFromStream($fh, $internalDir . $filename, $filesize);
Change: $this->addFileFromStream($fh, iconv("utf-8", "cp866", $internalDir.$filename), $filesize);

My Server configuration:
Operating system: Ubuntu 16.04.01 TLS
Web server: apache
Database: mysql
PHP version: 7
ownCloud version: 9.1
kalinkin_43@mail.ru