Problem converting from 2.4.8.3 to 3.1.2.1

Can someone help me?
when I put to convert the base I get the following error:
thrown in SubmissionFileManager.inc.php on line 184
Graciously

Can you share more of the output from the upgrade process? It might be helpful to simply paste the full output.

Query: UPDATE email_templates_default_data SET body=REPLACE(body, ‘{$editorialContactName}’, ‘Επιμελητές’) WHERE locale = ‘el_GR’ AND email_key IN (‘REVIEW_CONFIRM’, ‘REVIEW_DECLINE’) failed. Illegal mix of collations (latin1_swedish_ci,IMPLICIT), (utf8mb4_general_ci,COERCIBLE), (utf8mb4_general_ci,COERCIBLE) for operation ‘replace’
1270: Illegal mix of collations (latin1_swedish_ci,IMPLICIT), (utf8mb4_general_ci,COERCIBLE), (utf8mb4_general_ci,COERCIBLE) for operation ‘replace’
ADOConnection._Execute(UPDATE email_templates_default_data SET body=REPLACE(body, ‘{$editorialContactName}’, ‘Επιμελητές’) WHERE locale = 'el…, false)% line 1051, file: /tmp/ojs-3.1.2-1/lib/pkp/lib/adodb/adodb.inc.php
ADOConnection.Execute(UPDATE email_templates_default_data SET body=REPLACE(body, ‘{$editorialContactName}’, ‘Επιμελητές’) WHERE locale = 'el…)% line 446, file: /tmp/ojs-3.1.2-1/lib/pkp/classes/install/Installer.inc.php
Installer.executeSQL(UPDATE email_templates_default_data SET body=REPLACE(body, ‘{$editorialContactName}’, ‘Επιμελητές’) WHERE locale = 'el…)% line 441, file: /tmp/ojs-3.1.2-1/lib/pkp/classes/install/Installer.inc.php
Installer.executeSQL(Array[112])% line 399, file: /tmp/ojs-3.1.2-1/lib/pkp/classes/install/Installer.inc.php
Installer.executeAction(Array[3])% line 265, file: /tmp/ojs-3.1.2-1/lib/pkp/classes/install/Installer.inc.php
ERROR: Upgrade failed: DB: Illegal mix of collations (latin1_swedish_ci,IMPLICIT), (utf8mb4_general_ci,COERCIBLE), (utf8mb4_general_ci,COERCIBLE) for operation ‘replace’

Check to ensure that your config.inc.php localization settings are the same in 3.x as in 2.x:

If your upgrade also involves a server change, ensure that your new database collation matches your old database collation.

guys, another problem now. Can you help me?

(mysqli): SELECT s.*, ps.date_published,
COALESCE(stl.setting_value, stpl.setting_value) AS section_title,
COALESCE(sal.setting_value, sapl.setting_value) AS section_abbrev
FROM submissions s
LEFT JOIN published_submissions ps ON (s.submission_id = ps.submission_id)
JOIN sections se ON se.section_id = s.section_id
LEFT JOIN section_settings stpl ON (se.section_id = stpl.section_id AND stpl.setting_name = ‘title’ AND stpl.locale = ‘pt_BR’)
LEFT JOIN section_settings stl ON (se.section_id = stl.section_id AND stl.setting_name = ‘title’ AND stl.locale = ‘pt_BR’)
LEFT JOIN section_settings sapl ON (se.section_id = sapl.section_id AND sapl.setting_name = ‘abbrev’ AND sapl.locale = ‘pt_BR’)
LEFT JOIN section_settings sal ON (se.section_id = sal.section_id AND sal.setting_name = ‘abbrev’ AND sal.locale = ‘pt_BR’)
WHERE s.submission_id = 3887

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(mysqli): SELECT * FROM submission_settings WHERE submission_id = ‘3887’

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Fatal error: Uncaught Error: Call to a member function getFileId() on null in /home/webuser/revistas/ojs-3.1.2-1/lib/pkp/classes/file/SubmissionFileManager.inc.php:184
Stack trace:
#0 /home/webuser/revistas/ojs-3.1.2-1/classes/install/Upgrade.inc.php(1473): SubmissionFileManager->copyFileToFileStage(‘9030’, 1, 4, NULL, true)
#1 /home/webuser/revistas/ojs-3.1.2-1/lib/pkp/classes/install/Installer.inc.php(421): Upgrade->provideSupplementaryFilesForReview(Object(Upgrade), Array)
#2 /home/webuser/revistas/ojs-3.1.2-1/lib/pkp/classes/install/Installer.inc.php(265): Installer->executeAction(Array)
#3 /home/webuser/revistas/ojs-3.1.2-1/lib/pkp/classes/install/Installer.inc.php(186): Installer->executeInstaller()
#4 /home/webuser/revistas/ojs-3.1.2-1/lib/pkp/classes/cliTool/UpgradeTool.inc.php(88): Installer->execute()
#5 /home/webuser/revistas/ojs-3.1.2-1/lib/pkp/classes/cliTool/UpgradeTool.inc.php(64): UpgradeTool->upgrade()
#6 /home/webuser/revistas/ojs-3.1.2-1/tools/upgrade.php(34): UpgradeTool->execute()
#7 {main}
thrown in /home/webuser/revistas/ojs-3.1.2-1/lib/pkp/classes/file/SubmissionFileManager.inc.php on line 184

Did you pull those SQLs from another similar post? If so, it might be helpful to everyone to consolidate similar questions, rather than asking independent questions in a single thread.

The error Call to a member function getFileId() on null in .../lib/pkp/classes/file/SubmissionFileManager.inc.php:184 is also mentioned in:

and

and

In this last thread, the user reports that this was found to be an issue with missing supplementary files on the server.

Sorry, but can anyone help me with this error? Has anyone ever experienced this? Thanks.