I am extremely new to latex and I have to submit a project report in my college. The college has provided us with a template which we have to use for generating the report. It contains too many packages and other things which I am not familiar with. As I a extremely short on time, I need some help to fix the subsection numbering issue.
The packages included are:
\documentclass[oneside,a4paper,12pt]{book}
%\usepackage{showframe}
%\hoffset = 8.9436619718309859154929577464789pt
%\voffset = 13.028169014084507042253521126761pt
\usepackage{fancyhdr}
\fancypagestyle{plain}{%
\fancyhf{}
\fancyfoot[CE]{Pune Institute of Computer Technology, Department of Computer Engineering 2016-17}
\fancyfoot[RE]{\thepage}
}
\pagestyle{fancy}
\fancyhead{}
\renewcommand{\headrulewidth}{0pt}
\footskip = 0.625in
\cfoot{}
\rfoot{}
\usepackage[]{hyperref}
\usepackage{tikz}
\usetikzlibrary{arrows,shapes,snakes,automata,backgrounds,petri}
\usepackage{titlesec}
\usepackage{tabularx}
\usepackage[nottoc,notlot,notlof,numbib]{tocbibind}
\usepackage[titletoc]{appendix}
\usepackage{titletoc}
\renewcommand{\appendixname}{Annexure}
\renewcommand{\bibname}{References}
\setcounter{secnumdepth}{5}
\usepackage{float}
\usepackage{subcaption}
\usepackage{multirow}
\usepackage[ruled,vlined]{algorithm2e}
\begin{document}
....
after some pages of acknowledgments and abstract, this comes
\tableofcontents
\listoffigures
\listoftables
\mainmatter
\titleformat{\chapter}[display]
{\fontsize{16}{15}\filcenter}
{\vspace*{\fill}
\bfseries\LARGE\MakeUppercase{\chaptertitlename}~\thechapter}
{1pc}
{\bfseries\LARGE\MakeUppercase}
[\thispagestyle{empty}\vspace*{\fill}\newpage]
....
Then comes first chapter
\setlength{\parindent}{11mm}
\chapter{Synopsis}
\section{Project Title}
blah blah blah...
\section{ Project Option }
blah blah blah...
The PDF output that I see is (I use TexStudio in ubuntu 16.04)

The numbering is correctly displayed in the table of contents but it is not displayed in the chapters. I have uploaded all the info I felt that will be necessary to understand the problem. If you want anymore info, please feel free to ask for it. Thank you.
titlesecversion do you use? Maybe you have the same issue as http://tex.stackexchange.com/q/299969/43317 – esdd Apr 06 '17 at 08:12tilesecversion. I didn't notice its version. But now I have updated it (as given in the answer below). – Pranjal Apr 10 '17 at 18:50\hoffsetwith precision on an atom? – Johannes_B Apr 11 '17 at 05:15