Latest coc requires setting these

.vimrc

@@ -950,9 +950,26 @@ nmap <silent> <leader>me <Plug>(coc-command)expandMacro
 nmap <silent> <leader>gh :CocCommand clangd.switchSourceHeader<CR>
 nmap <silent> <leader>gH :CocCommand clangd.switchSourceHeader vsplit<CR>
 nmap <silent> <leader>gsi :CocCommand clangd.SymbolInfo<CR>
+
+" From coc-completion-help 2022-08-01
+inoremap <expr> <cr> coc#pum#visible() ? coc#_select_confirm() : "\<CR>"
+
 " Use K to show documentation in preview window
 nnoremap <silent> K :call <SID>show_documentation()<CR>
 
+  function! s:check_back_space() abort
+    let col = col('.') - 1
+    return !col || getline('.')[col - 1]  =~ '\s'
+  endfunction
+
+  " Insert <tab> when previous text is space, refresh completion if not.
+  inoremap <silent><expr> <TAB>
+	\ coc#pum#visible() ? coc#pum#next(1):
+	\ <SID>check_back_space() ? "\<Tab>" :
+	\ coc#refresh()
+  inoremap <expr><S-TAB> coc#pum#visible() ? coc#pum#prev(1) : "\<C-h>"
+
+
 function! s:show_documentation()
     if (index(['vim','help'], &filetype) >= 0)
         execute 'h '.expand('<cword>')