Upgradation DB error ojs 2.4.8 to ojs 3.2.1

this error appear and how to solve this, kindly help…

The collation was set by default at the time of installation.

2error ojs
Errors occurred during installation:

  • A database error has occurred: Illegal mix of collations (latin1_swedish_ci,IMPLICIT), (utf8_general_ci,COERCIBLE), (utf8_general_ci,COERCIBLE) for operation ‘replace’

my dump file Collation are “latin1_swedish_ci”. can we change this to other Collation, if yes then which Collation we select.

I am trying this but some table showing error:
ALTER TABLE article_search_keyword_list CHANGE keyword_text keyword_text VARCHAR(60) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL;

MYSQL said:

Duplicate entry ‘ayme’ for key ‘article_search_keyword_text’