2021/01/27 (更新內容)
CMMI是由美國卡內基美隆大學(Carnegie Mellon University)的軟體工程學院(Software Engineering Institute)開發，現在則是屬於CMMI Institute，CMMI Institute在2016年被ISACA收購。CMMI最新的版本是2018年提出的CMMI 2.0。
CMMI 2.0將產品與服務開發: CMMI for development (CMMI-DEV)、服務建置與管理: CMMI for services (CMMI-SVC)、產品與服務取得: CMMI for acquisition (CMMI-ACQ)整合成CMMI 2.0，然而，根據不同的需求，提供Development、Services及Supplier Management三個View。
CMMI 2.0將流程領域做了不一樣的分類，首先。新增了能力領域(Capability Area, CA)，在每個能力領域下又有多個實作領域(Practice Area, PA)，這些實作領域大概就是過去的流程領域，跟1.3比較，有一些新增(如:GOV、II)、合併(如:RDM、VV)及從原本的PA中獨立成PA(如:EST、PR)的部分。CMMI 2.0將CA分為四個類型:Doing、Managing、Enabling及Improving。
CMMI 1.X將PA根據成熟度進行切割，可是，CMMI 2.0又回到CMM的原本方式，各PA中訂定了不同的成熟度的標準，這雖然對於取得認證而言是比較複雜(每個流程領域都要進行)，但卻是比較符合實際的需求。
以CMMI Development 2.0而言，CA與PA的關係是:
Doing
Ensuring Quality (ENQ)
Requirement Development & Management (RDM)
Process Quality Assurance (PQA)
Verification & Validation (VV)
Peer Review (PR)
Engineering & Developing Products (EDP)
Technical Solution (TS)
Product Integration (PI)
Selecting & Managing Suppliers (SMS)
Supplier Agreement Management (SAM)
Managing
Planning and Managing Work (PMW)
Estimation (EST)
Planning (PLAN)
Monitor & Control (MC)
Managing Business Resilience (MBR)
Risk & Opportunity Management (RSK)
Managing the Work Force (MWF)
Organizational Training (OT)
Enabling
Supporting Implementation (SI)
Causal Analysis and Resolution (CAR)
Decision Analysis and Resolution (DAR)
Configuration Management (CM)
Improving
Building & Sustaining Capability (BSC)
Governance (GOV)
Implementation Infrastructure (II)
Improving Performance (IMP)
Process Management (PCM)
Process Asset Development (PAD)
Managing Performance & Measurement (MPM)
CMMI (1.X)分3個版本:
產品與服務開發: CMMI for development (CMMI-DEV)
服務建置與管理: CMMI for services (CMMI-SVC)
產品與服務取得: CMMI for acquisition (CMMI-ACQ)
CMMI與其他標準最大不同之處是CMMI提出成熟模式，也就是流程是逐步成熟，不是ㄧ步到位，CMMI將成熟度分為:
Level 1: Initial
Level 2: Managed
Level 3: Defined
Level 4: Quantitatively Managed
Level 5: Optimizing
將所有的流程分為五個成熟度 (以CMMI-DEV 1.3為例) :
Level 2 是軟體開發的基本流程
Project Planning (PP)
Project Monitoring and Control (PMC)
Requirements Management (REQM)
Supplier Agreement Management (SAM)
Configuration Management (CM)
Measurement and Analysis (MA)
Process and Product Quality Assurance (PPQA)
Level 3 開始建立組織級的管理流程
Organizational Process Definition (OPD)
Organizational Process Focus (OPF)
Organizational Training (OT)
Integrated Project Management (IPM)
Risk Management (RSKM)
Product Integration (PI)
Requirements Development (RD)
Technical Solution (TS)
Validation (VAL)
Verification (VER)
Decision Analysis and Resolution (DAR)
Level 4 基於前兩級所收集的資料，進行量化管理
Organizational Process Performance (OPP)
Quantitative Project Management (QPM)
Level 5 基於量化管理的基礎，進行最佳化
Organizational Performance Management (OPM)
Causal Analysis and Resolution (CAR)
也可將所有的流程分為四大流程領域 (以CMMI-DEV 1.3為例) :
Process Management
Level 3
Organizational Process Definition (OPD)
Organizational Process Focus (OPF)
Organizational Training (OT)
Level 4
Organizational Process Performance (OPP)
Level 5
Organizational Performance Management (OPM)
Project Management
Level 2
Project Planning (PP)
Project Monitoring and Control (PMC)
Requirements Management (REQM)
Supplier Agreement Management (SAM)
Level 3
Integrated Project Management (IPM)
Risk Management (RSKM)
Level 4
Quantitative Project Management (QPM)
Engineering
Level 3
Product Integration (PI)
Requirements Development (RD)
Technical Solution (TS)
Validation (VAL)
Verification (VER)
Support
Level 2
Configuration Management (CM)
Measurement and Analysis (MA)
Process and Product Quality Assurance (PPQA)
Level 3
Decision Analysis and Resolution (DAR)
Level 5
Causal Analysis and Resolution (CAR)