Dave Mackinnon has taken action over "unacceptable" posts and invited fans to face-to-face talks.
The Albanian winger has returned to Osijek after 18 months in Glasgow.
St Johnstone will move season ticket holders to offer seats to fans of the Glasgow clubs.
The Manchester United midfielder has suffered a knee injury that will keep him out for "months".
Celtic made the claim after Rangers said striker Alfredo Morelos was subjected to racist abuse.
Notice of complaint issued with disciplinary hearing to take place on Monday.
Celtic vow to investigate any reports of racist abuse directed at Rangers striker.
Scotland's oldest football club will leave Hampden Park at the end of the season.
Dyer was appointed caretaker after Angelo Alessio was sacked earlier this month.
The former Ibrox player was caught on camera making a w****r gesture.
Managing director Stewart Robertson says the club "suffered from errors of judgement".
The Celtic captain says his side will come back from their winter break stronger and fitter for the challenge ahead.
The Croatian defender says his team played without fear at the home of their rivals.
The interim boss says the issue has to be sorted during the winter break.
Derek McInnes says he will be active in the transfer market if the defender needs replaced.
The Celtic boss said his side didn't deserve to win but shouldn't have lost to Rangers.
The Rangers boss says his side's 2-1 win at Celtic Park is his best in management.
Goals from Ryan Kent and Nikola Katic gave the visitors victory at Celtic Park.
The sides go head to head in the last Glasgow derby of 2019.
Mr Weir and wife Chris, from Largs in North Ayrshire, claimed the £161m prize in July 2011.