Note: if you are using version 1.7 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 1.9, more info.
Note: after upgrade all data will be saved.
Do database backup
Rewrite all files from rukovoditel_1.9.zip
If you are using Extension then rewrite all files from rukovoditel_ext_1.5.zip in /plugins folder
If you are using Extension then run /install/ext_autoupdate/from_1.4_to_1.5.php
Remove /install folder
If you have any questions then ask in comments bellow.