Note: if you are using version 1.6 or earlier, you need to consistently perform all database updates to the current version. Rewrite all files from new version and follow the instructions from the update archive.
Note: if you are using extra translation, then before upgrade you have to upgrade language files. If your translation is not available yet, you can create a translation for version 1.8, more info.
Note: after upgrade all data will be saved.
Make a database and a file /config/server.php backups
Rewrite all files from rukovoditel_1.8.zip Note: because the file /config/server.php will be overwritten, open the new file and make your changes if you did it before.
If you are using Extension, then rewrite all files from rukovoditel_ext_1.4.zip in /plugins folder (You can download Extension under My Account page)
Run /install/autoupdate/from_1.7_to_1.8.php Note: you need to run this scripts in a web browser, for example:
Run /install/autoupdate/data_prepare_from_1.7_to_1.8.php Note: wait for the response OK for all Entities
If you are using Extension, then run /install/ext_autoupdate/from_1.3_to_1.4.php
Remove /install folder
If you have any questions, then ask in a comments bellow.