Anyone please give step by step method to upgrade ojs-2.4.8 to ojs-3.0.2 without data lose
hi i did the following steps, but still showing error 404.
For example:
Backuped my 2.4.8 database (mysqldump -u myuser -p --databases=myojsdb).
Backup my 2.4.8 uploaded files (tar -czvf /tmp/files_dir.tgz /path/to/private/ojs_files/).
Backup my 2.4.8 source code files (tar -czvf /tmp/ojs_source.tgz /path/to/webserver/ojs-2.8.2/).
Create a new install of OJS3.0.2 (tar -xzvf ojs-3.0.2.tar.gz -C /path/to/webserver/ojs-3.0.2/)
Copy the public files from 2.4.8 to 3.0.2 (sudo cp -rv /path/to/webserver/ojs-2.8.2/public/* /path/to/webserver/ojs-3.0.2/public/).
updated new config.inc.php file in ojs-3.0.2 to align with my previous configuration.
Changed “installed = Off”
Upgraded the OJS successfully .
But the data is missing.
Here is the database tables
ojs-2.8.2 database 
show tables
→ ;
±--------------------------------------+
| Tables_in_ojs |
±--------------------------------------+
| access_keys |
| announcement_settings |
| announcement_type_settings |
| announcement_types |
| announcements |
| article_comments |
| article_files |
| article_galley_settings |
| article_galleys |
| article_html_galley_images |
| article_search_keyword_list |
| article_search_object_keywords |
| article_search_objects |
| article_settings |
| article_supp_file_settings |
| article_supplementary_files |
| article_xml_galleys |
| articles |
| auth_sources |
| author_settings |
| authors |
| books_for_review |
| books_for_review_authors |
| books_for_review_settings |
| captchas |
| citation_settings |
| citations |
| comments |
| completed_payments |
| controlled_vocab_entries |
| controlled_vocab_entry_settings |
| controlled_vocabs |
| custom_issue_orders |
| custom_section_orders |
| data_object_tombstone_oai_set_objects |
| data_object_tombstone_settings |
| data_object_tombstones |
| dataverse_files |
| dataverse_studies |
| edit_assignments |
| edit_decisions |
| email_log |
| email_log_users |
| email_templates |
| email_templates_data |
| email_templates_default |
| email_templates_default_data |
| event_log |
| event_log_settings |
| external_feed_settings |
| external_feeds |
| filter_groups |
| filter_settings |
| filters |
| gifts |
| group_memberships |
| group_settings |
| groups |
| institutional_subscription_ip |
| institutional_subscriptions |
| issue_files |
| issue_galley_settings |
| issue_galleys |
| issue_settings |
| issues |
| journal_settings |
| journals |
| metadata_description_settings |
| metadata_descriptions |
| metrics |
| mutex |
| notes |
| notification_mail_list |
| notification_settings |
| notification_subscription_settings |
| notifications |
| oai_resumption_tokens |
| object_for_review_assignments |
| object_for_review_persons |
| object_for_review_settings |
| objects_for_review |
| paypal_transactions |
| pln_deposit_objects |
| pln_deposits |
| plugin_settings |
| processes |
| published_articles |
| queued_payments |
| referral_settings |
| referrals |
| review_assignments |
| review_form_element_settings |
| review_form_elements |
| review_form_responses |
| review_form_settings |
| review_forms |
| review_object_metadata |
| review_object_metadata_settings |
| review_object_type_settings |
| review_object_types |
| review_rounds |
| roles |
| rt_contexts |
| rt_searches |
| rt_versions |
| scheduled_tasks |
| section_editors |
| section_settings |
| sections |
| sessions |
| signoffs |
| site |
| site_settings |
| static_page_settings |
| static_pages |
| subscription_type_settings |
| subscription_types |
| subscriptions |
| temporary_files |
| theses |
| usage_stats_temporary_records |
| user_interests |
| user_settings |
| users |
| versions |
±--------------------------------------+
125 rows in set (0.00 sec)
OJS-3.0.2
show tables;
±--------------------------------------+
| Tables_in_ojs_ss |
±--------------------------------------+
| access_keys |
| announcement_settings |
| announcement_type_settings |
| announcement_types |
| announcements |
| auth_sources |
| author_settings |
| authors |
| citation_settings |
| citations |
| completed_payments |
| controlled_vocab_entries |
| controlled_vocab_entry_settings |
| controlled_vocabs |
| custom_issue_orders |
| custom_section_orders |
| data_object_tombstone_oai_set_objects |
| data_object_tombstone_settings |
| data_object_tombstones |
| edit_decisions |
| email_log |
| email_log_users |
| email_templates |
| email_templates_data |
| email_templates_default |
| email_templates_default_data |
| event_log |
| event_log_settings |
| filter_groups |
| filter_settings |
| filters |
| genre_settings |
| genres |
| gifts |
| institutional_subscription_ip |
| institutional_subscriptions |
| issue_files |
| issue_galley_settings |
| issue_galleys |
| issue_settings |
| issues |
| item_views |
| journal_settings |
| journals |
| library_file_settings |
| library_files |
| metadata_description_settings |
| metadata_descriptions |
| metrics |
| mutex |
| notes |
| notification_mail_list |
| notification_settings |
| notification_subscription_settings |
| notifications |
| oai_resumption_tokens |
| paypal_transactions |
| plugin_settings |
| processes |
| published_submissions |
| queries |
| query_participants |
| queued_payments |
| review_assignments |
| review_files |
| review_form_element_settings |
| review_form_elements |
| review_form_responses |
| review_form_settings |
| review_forms |
| review_round_files |
| review_rounds |
| rt_contexts |
| rt_searches |
| rt_versions |
| scheduled_tasks |
| section_editors |
| section_settings |
| sections |
| sessions |
| site |
| site_settings |
| stage_assignments |
| static_page_settings |
| static_pages |
| submission_artwork_files |
| submission_comments |
| submission_file_settings |
| submission_files |
| submission_galley_settings |
| submission_galleys |
| submission_html_galley_images |
| submission_search_keyword_list |
| submission_search_object_keywords |
| submission_search_objects |
| submission_settings |
| submission_supplementary_files |
| submission_tombstones |
| submissions |
| subscription_type_settings |
| subscription_types |
| subscriptions |
| temporary_files |
| usage_stats_temporary_records |
| user_group_settings |
| user_group_stage |
| user_groups |
| user_interests |
| user_settings |
| user_user_groups |
| users |
| versions |
±--------------------------------------+
112 rows in set (0.00 sec)