Hi @bozana,
I did what Asmecher suggested in the post I quoted above, putting a section for all articles that did not already have a section and manually deleting, through the web interface, all records of supplemental files that did not have the files.
Now I’m encountering the following errors:
[version: 3.1.0.0]
[code: Installer Installer::syncSeriesAssocType]
[data: dbscripts/xml/upgrade/2.4.0_preupdate_usageStatistics.xml (skipped)]
[data: dbscripts/xml/upgrade/2.4.0_preupdate_usageStatistics2.xml (skipped)]
[code: Installer Installer::removeReviewEntries]
[data: dbscripts/xml/upgrade/3.0.0_preupdate.xml]
[data: dbscripts/xml/upgrade/3.0.0_adaptTimedViews.xml (skipped)]
[data: dbscripts/xml/upgrade/3.0.0_adaptReferrals.xml]
[data: dbscripts/xml/upgrade/3.0.0_adaptBooksForReview.xml]
[data: dbscripts/xml/upgrade/remove_timed_views_bots.xml (skipped)]
[data: dbscripts/xml/upgrade/3.0.0_preupdate_commentsToEditor.xml]
[code: Installer Installer::concatenateIntoAbout]
[code: Installer Installer::concatenateIntoMasthead]
[data: dbscripts/xml/upgrade/3.1.0_preupdate_review_assignments.xml]
[data: dbscripts/xml/upgrade/3.1.0_preupdate_notes.xml]
[data: dbscripts/xml/upgrade/3.1.0_preupdate_payments.xml]
[schema: lib/pkp/xml/schema/common.xml]
[schema: lib/pkp/xml/schema/log.xml]
[schema: lib/pkp/xml/schema/announcements.xml]
[schema: lib/pkp/xml/schema/scheduledTasks.xml]
[schema: lib/pkp/xml/schema/temporaryFiles.xml]
[schema: lib/pkp/xml/schema/metadata.xml]
[schema: lib/pkp/xml/schema/reviews.xml]
[schema: lib/pkp/xml/schema/reviewForms.xml]
[schema: lib/pkp/xml/schema/controlledVocab.xml]
[schema: lib/pkp/xml/schema/submissions.xml]
[schema: lib/pkp/xml/schema/submissionFiles.xml]
[schema: lib/pkp/xml/schema/notes.xml]
[schema: lib/pkp/xml/schema/views.xml]
[schema: lib/pkp/xml/schema/genres.xml]
[schema: lib/pkp/xml/schema/tombstone.xml]
[schema: lib/pkp/xml/schema/rolesAndUserGroups.xml]
[schema: lib/pkp/xml/schema/metrics.xml]
[schema: lib/pkp/xml/schema/views.xml]
[schema: lib/pkp/xml/schema/libraryFiles.xml]
[schema: lib/pkp/xml/schema/navigationMenus.xml]
[schema: dbscripts/xml/ojs_schema.xml]
[data: dbscripts/xml/indexes.xml]
[code: Installer Installer::migrateCounterPluginUsageStatistics (skipped)]
[code: Installer Installer::migrateTimedViewsUsageStatistics (skipped)]
[code: Installer Installer::migrateDefaultUsageStatistics (skipped)]
[data: dbscripts/xml/upgrade/2.4.0_postUsageStatsMigration.xml (skipped)]
[data: dbscripts/xml/upgrade/2.4.0_postUsageStatsMigration2.xml (skipped)]
[data: dbscripts/xml/upgrade/2.4.0_postCounterMigration.xml (skipped)]
[data: dbscripts/xml/upgrade/2.4.0_postTimedViewsMigration.xml (skipped)]
[data: dbscripts/xml/upgrade/3.0.0_change_assoc_type.xml]
[data: dbscripts/xml/upgrade/3.0.0_change_assoc_type_metrics.xml]
[data: dbscripts/xml/upgrade/3.0.0_settings.xml]
[code: Installer Installer::installDefaultGenres]
[code: Installer Installer::migrateArticleMetadata]
[data: dbscripts/xml/upgrade/3.0.0_update.xml]
[code: Installer Installer::clearDataCache]
[code: Installer Installer::migrateUserRoles]
[code: Installer Installer::fixReviewForms]
[code: Installer Installer::htmlifyEmailTemplates]
[note: docs/release-notes/README-BEACON]
[code: Installer Installer::installEmailTemplate]
[code: Installer Installer::installEmailTemplate]
[code: Installer Installer::installEmailTemplate]
[code: Installer Installer::installEmailTemplate]
[code: Installer Installer::installEmailTemplate]
[code: Installer Installer::installEmailTemplate]
[data: dbscripts/xml/upgrade/3.0.0_scheduledTasks.xml]
[code: Installer Installer::localizeCustomBlockSettings]
[code: Installer Installer::convertEditorDecisionNotes]
[code: Installer Installer::convertQueries]
[code: Installer Installer::migrateFiles]
[code: Installer Installer::convertSupplementaryFiles]
[code: Installer Installer::setFileUploader]
[code: Installer Installer::setFileName]
[data: dbscripts/xml/upgrade/3.0.0_postupdate.xml]
[data: dbscripts/xml/upgrade/3.0.0_pubId_settings.xml]
[data: dbscripts/xml/upgrade/3.0.0_postupgrade_galley_files.xml]
[data: dbscripts/xml/upgrade/3.0.0_postupgrade_metrics.xml]
[data: dbscripts/xml/upgrade/3.0.0_issue_settings.xml]
[data: dbscripts/xml/upgrade/3.0.0_submission_settings.xml]
[data: dbscripts/xml/upgrade/3.0.0_review_method.xml]
[data: dbscripts/xml/upgrade/3.0.0_edit_decisions.xml]
[code: Installer Installer::convertCommentsToEditor]
PHP Warning: Element '<ahref|target><em><strong><cite>& lt;code><ul><ol><li><dl><dt><dd><b> <i><u><imgsrc|alt><sup><sub><br><p>' i s not supported (for information on implementing this, see the support forums) in /var/www/ojs-3.1.0/lib/pkp/lib/vendor/ezyang/htmlpurifier/library/HTMLPurifie r/HTMLDefinition.php on line 311
[note: docs/release-notes/README-3.0]
[note: docs/release-notes/README-3.0.1]
[data: dbscripts/xml/upgrade/3.0.2_update.xml]
[note: docs/release-notes/README-3.0.2]
[code: Installer Installer::moveReviewerFiles]
ERROR: Reviewer files with ID 5871 from review assignment 696 could not be found in the database table submission_files
ERROR: Reviewer files with ID 6899 from review assignment 872 could not be found in the database table submission_files
ERROR: Reviewer files with ID 6694 from review assignment 884 could not be found in the database table submission_files
ERROR: Reviewer files with ID 9692 from review assignment 1457 could not be foun d in the database table submission_files
ERROR: Reviewer files with ID 16668 from review assignment 3323 could not be fou nd in the database table submission_files
ERROR: Reviewer files with ID 19075 from review assignment 4319 could not be fou nd in the database table submission_files
ERROR: Reviewer files with ID 28613 from review assignment 6584 could not be fou nd in the database table submission_files
ERROR: Reviewer files with ID 28125 from review assignment 6585 could not be fou nd in the database table submission_files
ERROR: Reviewer files with ID 44439 from review assignment 10663 could not be fo und in the database table submission_files
ERROR: Reviewer files with ID 48910 from review assignment 11938 could not be fo und in the database table submission_files
ERROR: Reviewer files with ID 42013 from review assignment 10427 could not be fo und in the database table submission_files
ERROR: Reviewer files with ID 47250 from review assignment 12106 could not be fo und in the database table submission_files
[code: Installer Installer::fixAuthorGroup]
[data: dbscripts/xml/upgrade/3.0.0_reviewer_files.xml]
ERROR: Upgrade failed: DB: ERROR: null value in column "review_round_id" violat es not-null constraint
DETALHE: Failing row contains (4024, null, 3, 7952, 1).
Can you help me, please?!