I opened a 2.79 project in 2.8 but some objects were in different layer panel and hidden. How can i unhide them and show on viewport?
After opening files from 2.79 the objects that were on a different layer that was not visible before saving the file have the disable in viewport restriction toggle enabled, which is not shown by default. To make the disable in viewport restriction toggle show, open the filter menu in the outliner and enable the disable in viewport in restriction toggles (the monitor icon). After that you can enable everything that was hidden back.